TRANSCRIBER’S NOTE
Italic text is denoted by _underscores_.
Bold text is denoted by =equal signs=.
Underlined text is denoted by __double underscores__.
Overlined text is denoted by @at symbols@. Overlines from square and
cube root notations (²√ and ³√, respectively) have been omitted.
Footnote anchors are denoted by [number], and the footnotes have been
placed at the end of the chapter.
A superscript is denoted by ^x or ^{xx}, for example und^r or 36^{th}.
Some minor changes to the text are noted at the end of the book.
This edition of the book did not include a Table of Contents. For
the convenience of the reader one has been created here:
Preface.
Index.
Part I. Arithmetic, Geometry, Drawing, Etc.
Arithmetic.
Some Signs Employed in Calculations.
Powers and Roots.
Proportion.
Elements of Practical Geometry.
Geometrical Drawing.
Drawing Instruments.
Geometrical Drawings.
the Micrometrical Dividing Table.
Other Methods of Dividing Into Equal Parts.
to Subdivide a Circle.
Time.
Part II. Materials Employed in Horology.
Iron.
Cast Iron.
Steel.
General Observations.
Special Observations.
Determination of the Qualities of Steel.
Preparations of Steel.
Hardening.
Tempering.
to Whiten and Blue Steel.
Case-hardening.
Influence of Foreign Metals and Metalloids on the
Qualities of Iron and Steel.
Copper.
Zinc.
Brass.
Hammer Hardening of Brass.
to Anneal Brass.
Cast Brass.
Tin.
Bronze.
Sterro.
Lead.
Nickel.
German Silver.
Gold.
Silver.
Aluminium and Aluminium Bronze.
Mercury.
Platinum.
Palladium.
Characteristic Properties of Alloys.
Soldering.
Methods of Soldering.
Bronzing.
Gilding.
Acids and Salts.
Oil.
Alcohol.
Benzine, Etc.
Polishing Materials.
Preparation of Polishing Materials.
Smoothing.
Smoothing of Brass.
Smoothing of Steel.
Polishing.
to Polish Steel.
Cement, Wax, Resin, Etc.
Enamel.
Precious Stones.
Working in Precious Stones.
Part III. Health and Manipulation.
Preservation of Health.
the Sight.
the Body in General.
Use of the File and Graver.
to File Flat and Square With Both Hands at Once.
to File Flat With One Hand.
to Turn Cylindrical Pivots, Etc., and Square Shoulders.
Part IV. Tools and Appliances.
Workshop Fittings.
the Lathe.
the Foot Wheel.
the Bench.
Idlers.
Chucks.
the Slide Rest.
Gravers and Other Hand-turning Tools.
Drills.
Lathe Attachments.
Miscellaneous Small Tools.
Accessories and Miscellaneous Operations to Be Performed in the
Universal Head.
to Center an Object.
Uprighting and Drilling.
Production of Screw Threads. Screw Plates and Taps.
Taps.
Methods of Tapping Holes.
Rapid Mode of Making a Screw.
Screw-head Tools.
Tools For Cutting and Rounding-up the Teeth of Wheels.
Wheel-cutting Engine.
Cutters For Forming the Teeth of Brass Wheels.
Mill Cutters For Steel.
Tool For Making Cutters.
Tools For Correcting the Form of Teeth.
to Test the Accuracy of Certain Tools.
Part V. Repairing and Examining Watches.
Method.
External Examination of the Watch.
to Examine a Geneva Movement.
Accessories For Beginners.
Cleaning the Watch.
Putting the Watch Together.
to Examine English Or American Movements.
to Rapidly Time a Watch Or Clock.
Timing in Positions. Horizontal and Vertical.
Note on the Proportions of Balances.
Demagnetizing.
Part VI. Practical Recipes.
the Plate.
the Barrel. Including Arbor, Stopwork, Mainspring, Etc.
the Mainspring.
the Fusee.
Chain.
Wheels.
Pinions.
Set-hands Square.
Pivots.
Bushing Pivot Holes, Etc.
Depths.
on the Application of the Geometrical Laws of Depths to Practice.
Pallets.
Cylinder.
Balance Spring.
Dial Plate.
Metal Dials.
Hands.
Glasses.
Broaching.
Solid and Hollow Squares.
to Straighten a Rod, Plate Or Wheel.
American Watch Tool Co.
STONEY BATTER WORKS,
Chymistry District, WALTHAM, MASS.
[Illustration]
MAKERS OF THE CELEBRATED
WEBSTER-WHITCOMB LATHE
AND ATTACHMENTS.
Do not be deceived by an “IMITATION” when you can get the
Genuine Webster-Whitcomb for $36.00.
By the introduction of special and costly tools we have brought the
price of Lathes down from $80.00 in 1876, to $36.00 in 1894. Who has
done more for the craft than we?
SEND for Price List and NOTE reductions.
Remember our full address.
BENJ. ALLEN & CO.
141-143 STATE ST., CHICAGO, ILL.
Watch Materials, Tools and
__Jewelers’ Supplies__.
THE MOST COMPLETE STOCK.
LOWEST PRICES. BEST GOODS.
[Illustration: DIAMOND PIN TONGUES
Extra Quality
Manufactured Expresssly for
BENJ. ALLEN & CO,
141 & 143 State Street Chicago, Ill.]
“Diamond” Brand Pin Tongues, put up in neat box, partitioned off, each
size separate, warranted the best and stiffest Pins in the market, per
gross - =$1.00=.
_All Orders Filled Accurately and
Without Delay._
SEND FOR ILLUSTRATED CATALOGUE.
Watches, Clocks, Diamonds,
Jewelry and Silverware.
THE
WATCHMAKERS’ HAND BOOK
INTENDED AS A WORKSHOP COMPANION FOR THOSE ENGAGED
IN WATCHMAKING AND ALLIED MECHANICAL ARTS
BY CLAUDIUS SAUNIER
ILLUSTRATED AMERICAN EDITION
REVISED AND ENLARGED BY
HENRY G. ABBOTT
WITH SPECIAL REFERENCE TO THE WANTS OF AMERICAN WORKMEN
CHICAGO:
GEO. K. HAZLITT & CO., PUBLISHERS.
1894.
COPYRIGHTED 1892, BY GEO. K. HAZLITT & CO.
PREFACE.
M. Saunier’s writings occupy an unique position in Europe, as works of
reference for all who are engaged in watchmaking, and it may not be out
of place to observe that the American edition of his treatise promises
to take a similar place among English-speaking communities.
A glance at the index will show that the information given is
essentially practical in its character, and such as will be of use to
the watchmaker in his daily work. The volume is thus in no sense an
abridgment of the original edition, but on the contrary, it contains
much more matter than the original work.
In recent years the work of the ordinary watch repairer has undergone
considerable change. The apprenticeship he serves, if indeed it can be
called a real apprenticeship, is shorter than formerly. The immense
number of badly constructed watches that he is called upon to put in
going order for a trifling remuneration, compels him to replace the
older methods of procedure by others, whenever by so doing time can
be saved. From this point of view, then, the value of the present
Hand Book can hardly be over-estimated, since it contains, in a
readily accessible form, many details as to the working of metals, and
descriptions of various practical operations, new and improved forms of
tools, etc.
But the volume will be found of daily use to a wider circle of workers
than those above referred to. We believe that there is hardly a
branch of the watchmaking trade which may not benefit by the numerous
practical details that are given; indeed, although the work is
specially designed for the use of watchmakers, a great portion of it
will be seen to be no less applicable to other mechanical arts.
M. Saunier’s original works, the _Guide-Manuel de l’Horloger_, and
_Recueil des Procedes Pratiques_, which appeared as separate volumes,
have been incorporated in this American edition, a large amount of
additional information being at the same time added. As the second
contained many details that more properly belonged to the first, and
_vice versa_, it has been thought desirable to remodel the whole, and,
as will be seen from an examination, the six parts that constitute the
work are distinct in their character.
With a view to further facilitate the use of this Hand Book as a work
of daily reference, an unusually full index has been added, which the
reader is recommended in all cases to consult, and no effort has been
spared to make the cross references in the body of the work as complete
as possible.
It seems desirable here to give some explanation in regard to several
of the practical methods described. Every watchmaker will at once
recognize that recipes are included which are of the nature of
makeshifts, and that it would in many cases be better to replace a
piece by a new one rather than to repair it in the manner indicated.
But, on the other hand, it has been felt that the work will often be
appealed to by those who, from various circumstances, may be prevented
from making or procuring a new part that will suit the watch under
repair, while those who are not so situated will have no difficulty in
deciding for themselves as to which method to adopt.
The original work of M. Saunier, and the English edition, both had the
illustrations in the back of the work, which necessitated considerable
inconvenience when consulting them. In this edition we have ventured
to insert the illustrations in the text that describes them. The
antiquated tools, like the bow, bow-lathe, the turns and mandril,
have been omitted, and the modern foot-wheel, lathe and accessories
substituted.
HENRY G. ABBOTT
INDEX.
_NOTE—The references are in all cases to the pages, not to the
paragraphs._
A
Accuracy of tools, to test, 366
” ” rules, to test, 33
Acids, 127
Adjusting rod, to use, 433
Agate, 164
Akerman on hardening, 77
Alcohol, 132
” and glycerine on oilstones, 192
Alloys, 57
” properties of, 108
” that melt at certain temperatures, 82
Alum, 128
Aluminium, 103, 110
” bronze, 104, 110
” solders, 113, 116
Amalgams, 105
American chucks, 224
Ammonium, chloride of, 128
Angle of cutting edges, 235
Angles of escapement, to measure, 465
” measurement of, 26
” to construct equal, 44
” to subdivide, 44
Annealing brass, 96
” steel, 72
Anvil, to harden face of, 88
Appliances for watchmakers, 189
Aqua Regia, 127
Arbor, barrel, to make, 409, 420
” ” ” repair, 428
” ” ” true, 429
” chuck for wheel-cutting, 224, 337
” to straighten, 505
” nut, to drill, 425
” ” diameter of, 425
” set-hands, to adjust, 451
” ” ” tighten, 294
Area, measurement of, 25
Arithmetic, importance of, 17
Arithmetical ratio, 22
Automatic blow-pipe, 201
Ayr stone, 135
Axis of crystallization, 166
B
Back rests, 253
Balance, pivots, form of, 400
” poise of, 401
” protector, 265
” spring stud index, 280
” to make plain, 436
” vibrations of, 460
Balances, proportions of, 401
Balance spring, action of, 473
” ” collet tool, 286, 474
” ” gauge, 475
” ” to center, 377
” ” ” clean, 384
” ” ” draw, 47
” ” ” flatten, 477
” ” ” select, 478
” ” ” weaken, 477
Balance-springs, palladium, 107
” ” platinum, 107
Balas ruby, 162
Bands, 219
Barrel-arbor, to make, 409, 420
” ” ” repair, 428
” ” ” true, 429
” cover, to make, 410
” going, to put together, 385
” hole to bush, 412
” hook, to fix, 411
” clock, to make, 420
” to examine, 379
” ” make, 409
” ” oil, 388
” ” repair, 379, 412
” ” true, 379, 413
” ” upright, 413
Bars, to make, 409
Baths for hardening, 78
Beaupuy burnishers and files, 195
Beat block, 266
Beginners, aids for, 381
Bell-metal, 98
Belts for lathes, 219
Bench, 189, 221
Bent pivot, to redress, 454
Benzine, 133, 384
Berlioz rounding-up cones, 362
Berzelius pastile, 498
Black polish on steel, 154
Bleaching silver dials, 487
Blow-pipes, 199
Blow-pipe, gas, 201
” automatic, 201
Blue polishing stone, 135
Blueing steel, 86
Board, arrangements of, 177, 189
“Body” of steel, 70
Borax as flux for soldering, 128
Bouchons, movable, 456
” to make, 298, 456
” ” rivet, 456
Brass, 90, 110
” cast, 86, 110
” dials, to silver, 491
” etc., drill blade for, 241
” influence of impurities on, 91
” plates, to harden, 92
” rods, to harden, 95
” to anneal, 96
” ” bronze, 121
” ” polish, 149
” ” select, 91
” ” smooth, 139
” wheel teeth, observations on cutting, 346
” wheels, to polish, 149, 135
Brazing, 119
Breguet spring, to set, 476
Broaches, 199
Broaching, 499
” a hole round, 499
Brocot method of hardening brass rods, 95
Broken screw extractor, 262
” ” to remove with alum, 128
Bronze, 98, 110
” aluminium, 103, 110
” to render malleable, 98
Bronzing, 120
Brush, to clean with, 383
Brushes, preparation of, 382
Buff leather, 133
Burnishers, 198
” Beaupuy, 195
” to re-face, 198
Burnishing brass wheels, 135, 149
Burnt iron, 58
Bushing barrel holes, 412
” pivot-holes, 456
C
Caliper, figure-of-8, 197
” for heights, etc., 197
” micrometer, 270
” pallet, 466
” rest, jeweling, 249
” vernier, 278
Camphorated oil, 131
Cannon pinion, to tighten, 449
Carbon in cast iron and steel, 60
Carnelian, 164
Case hardening, 88
Case, to examine, 389
Cast brass, 90
” iron, 60
” steel, 61
Castings, malleable, 61
Catgut bands, to join, 219
Cement, application of, 156
” steel, 62
Center of circle, to find, 44
Centers, to test truth of, 366
” various, 266
Center wheel, 379
” ” to oil, 388
Centering attachments, 253
” from circumference, 307
” in wax, 157, 314
” methods of, 305
” rods, 285, 385
Chain, fusee, to ease, 434
Chain hook, to rivet, 434
Chalk for cleaning, 382
Chamfering tools, 281, 283
Charcoal for polishing, 133
” used for smoothing, 133
Chinese bronzing, 121
Chloride of ammonium, 128
” of zinc as flux for soldering, 118
Chrysolite, 163
Chucks, 224
Circle, divisions of, 24
” sub-division of, 52
” to find center of, 44
Circular oil stones, 191
Circumference, ratio to diameter, 25
” to center from, 307
Cleaning brushes, 383
” files, 193
” gold or gilt objects, 125
” metal dials, 491
” nickel movements, 101
” rough steel, 75
” watches, 382
Clock barrel, to make, 420
” dials, to clean, 491
” hands, to blue, 86
” pinions, to polish, 443
” to time rapidly, 394
Closing barrel holes, etc., 295
Cocks, to make, 409
Colcothar of vitriol, 135
Cold gilding without mercury, 122
” hammering, 74, 92
Collet, balance spring, tool, 286
Coloring gold dials, 493
Compass, proportional, 37
Compasses, 196
Conductivity, 110, 112
Copper, 89
” alloys with gold, 102
” to bronze, 120
Cord of lathe, 219
Countershaft, 220
Counting vibrations, 394
Cover of barrel, groove for, 410
” ” ” to make, 410
Crocus, 135
Crossing out a wheel, 435
Crossings of wheel, to mark, 298
” to renew broken, 440
Crystallization, axis of, 166
Cube root, 20
Curb, to adjust, 415
Cutters, to adjust form of, 353
” for jewels, 165
” ” making grooves, etc., 312
” ” slide rest, 286
” ” steel wheels, 347
” ” teeth, various kinds, 339
” rose and star, 349
” rounding up, to make, 331
” tool for making wheels, 353
” to sharpen slide rest, 287
” wheel, to make, 339
Cutting a file, 194
” edge, angles of, 235
” faces of gravers, forms of, 239
” glass, 498
” wheels, observations on, 310, 348
Cylinder escape wheel, to test, 290
” to oil, 388
” ” pivot a, 454
” ” polish mechanically, 468
D
Dead smoothing, 143
” surface of gold, to restore, 126
Decantation, 136
Definitions, geometrical, 23
Degrees of circle defined, 24
Demagnetizing watches, 403
Density, 108
Depth caliper, 197
Depths, application of laws of, 458, 460
” in stem-wind work, 462
” theoretical and practical, 458, 460
” to ease, 365
” ” secure good, 457
” visible and invisible, to test, 377
Depthing tool, to test accuracy of, 368
Design, to transfer, 30
Dial, enamel, to cut hole in, 484
” ” ” drill, 480
” ” ” reduce diameter of, 486
” ” ” remove figure from, 486
” plate, to cut, 479
” to file hole in, 481
” ” remove enamel from back of, 482
Dials, enamel for, 160
” fixed by feet, 483
” ” ” screws, 482
” gold, to restore, 493
” metal, to clean, 491
” silver, to restore, 487
” to paint hours on, 495
” ” repair, 161
Diamond, 161
” drill, to use, 169
” ” and gravers, 162, 173
” for polishing, 162
” powder, drilling with, 168
” ” to prepare, 135
Diamantine for polishing, 134, 154
Diameter, ratio to circumference, 25
Dies for screw-making, 315
” ” wheel-making, 438
Dividing plate, 298
” scales, etc., 48
” table, micrometrical, 48
Dome, freedom of, 389
Douzieme gauge, 196
Draw-plate, 298
Drawing, geometrical, 28, 40
” instruments, 32
” scales, 33
” to reduce a, 40
Drawn steel, advantages of, 71
Drifting, 296, 415, 502
Drifts, to make, 296, 422
Drill, diamond, 162, 173
” rest, 267
Drilling a barrel-arbor, 423
” enamel dial, 480
” glass, 498
” in the lathe, 308
” lubricants for, 480
” precautions in, 242, 244
” tool, to test accuracy of, 366
” with diamond powder, 168
Drills for oil-cups, 281
” to make, 244
” ” mount diamond, 173
” various, 241
Duplex ruby-roller, to make, 173
E
Elasticity of steel, 70, 84
Electro-gilding, 124
Elements of practical geometry, 23
Elevation defined, 28
Ellipse, to draw, 46
Emery, 134
” paper, to make, 134
” wheels and sticks, 134
Enamel, 159
” false, 161
” to apply cold, 160
” ” remove from back of dial, 482
” dial, to cut hole in, 484
” ” ” drill, 480
” ” ” erase figure from, 486
” ” ” reduce diameter of, 486
” dials fixed by feet, 483
” ” ” by screws, 482
Endshake, 375
Endstone, to fix, 159
” ” make, 171
Engine, wheel-cutting, 330
English movement, to examine, 389
Engraved design, to transfer, 30
Epicycloidal depths, 459
Equaling file, to cut, 194
Erasing figure from enamel dial, 486
Escapements, action of, 376
” gauges for, 465
” play of pivots in, 452
” to examine, 391
” ” measure angles of, 465
” ” oil, 387
Escapewheel, clip for holding, 289
” to test, 290
” cock passage, to turn, 312
Essences for cleaning, 133, 384
Examining watches, 371, 389
Expansion, 109
Extracting broken screws, 128, 262, 317
” square root of numbers, 21
Eyesight, to preserve, 175
F
Face-plate, 257
” universal, 257
False ruby, 163
Figure-of-8 calliper, 197
File, to cut equaling, 194
” ” round-up teeth with, 363
” use of, 178, 193
Files, Beaupuy, 195
” to clean, 193
” ” renew, 193
” ” set in handles, 193
Filing block, 269
” fixture, 268
” flat, 179
” rest, 269
” square by hand, 179, 182, 500
Finger-piece, to make, 418
Flat filing, 179
” ” device for, 182
” polishing, tool for, 302
Fletcher furnaces, 201
Fluxes for soldering, 117
Foot-wheel, 218
Fourth wheel, uprighting of, 379
Fraise, Ingold, 362
Freedom of various parts, 378, 375, 391
Frosted surface on steel, to produce, 144
Frosting silver dial, 487
Furnace temperatures, table of, 78
Furnaces, wind and muffle, 201
Fusee, advantages of, 432
” to adjust, 433
” ” snail, 145
” watch, to examine, 389
Fusion, points of, 110, 112
G
Gauges, 196
” for balance-springs, 475
” ” escapements, 465
” movement, table of, 462
” registering, 274
” staff, 275
Geneva movement, to examine, 374
Geometrical drawing, 28
” proportion, 22
” ratio, 20
Geometry, elements of practical, 23
” importance of, 17
German silver, 100, 110
Gilding, 122
” bath, to prepare, 124
Gilt objects, to clean, 125
Glass, to cement, 157
” ” cut, 498
” ” drill, 498
” use of, 175
Glue, application of, 156
Glycerine and alcohol on oilstones, 191
Gold, 101, 110
” to clean, 126
” ” deaden surface, 126
” ” prepare in powder, 128
” copper alloys, 102
” ” dials, to restore, 493
” solders, 114, 116
” springs, 102, 478
Graduations of scales, etc., 49
Grain of steel, 68
Graining prior to gilding, 125
” steel, 144
Grammaire, 298
Gravers, diamond, 162
” to mount diamond, 162
” use of, 178
” various, 238
Grinder, traverse spindle, 258
Grindstone, 192
Groove, circular, to cut, 311
” for barrel-cover, to make, 410
” straight, to make, 312
” to turn, 312
H
Hairspring, _see_ Balance spring.
” stud index, 280
Hairspringing collet tool, 286
Hammer hardening, 68, 74, 92
Hand fitting pliers, 288
” holder, 287
” to enlarge hole in, 287
” ” set in position, 497
” turning tools, 238
Hands, freedom of, 373
” to blue, 86
” ” to redden, 497
” ” tighten, 287
Handles, to set tools in, 198
Hard steel, to drill, 243
” ” ” turn, 185
Hardening brass, 92
” gold spring, 478
” solutions, 77
” steel, methods of, 77
” ” precautions in, 79
” ” temperature for, 68, 81
Hardness of jewels, to test, 166
” ” steel, 82
” scale of, 111
Health, preservation of, 175
Heat, mode of applying, to temper, 84
” of furnaces, table of, 78
Homogeneity of steel, 68
Hone slates, 134
Holder, escape wheel, 289
” for watch-hand, 287
Holes, methods of tapping, 323
Hook, chain, to rivet, 484
” to fix in barrel, 411
Hooks for catgut bands, 219
Hooked gravers, 288
Hours, to paint on dials, 495
” wheel, freedom of, 374
Hydrochloric acid, 127
” ” flux for soldering, 118
Hydrofluoric acid, 127
Hydrogen in palladium, 107
I
Idlers, 222
Impurities in brass, their influence, 90
” ” steel ” ”, 88
Index, to ease, 478
Ingold fraise, 362
Inks for painting dials, 496
Instruments, drawing, 82
Involute depths, 458
Iridium, alloy with platinum, 107
Iron, cast, 60, 110
” for soldering, 118
” its properties and uses, 57
” oxides of, for polishing, 185
” to case harden, 88
” ” distinguish from steel, 57
” ” restore, 59
” wrought, 57, 110
J
Jewel in pallet, to advance, 463
” resetting tool, 299
” setting, cutters for, 137
” to find axis of, 166
” holes, thickness of, 400
” ” to make, 168
” ” ” set, 171, 298
” ” ” smooth and polish, 169
Jeweling caliper rest, 249
Jewelry, alloys used for, 102
” to clean after soldering, 126
Jewels, 161
” to select, 166
” working in, 165
K
Keyless pinion, to drift, 503
” winding depths, 392, 462
” ” wheel, to make, 441
” work, need of oil, 383
” ” to examine, 392
L
Lamps, 190
Laps for jewelers, 165
Lathe, 210
” attachments, 247
” belts, 219
” care of, 213
” simple form of, 211
” for jewel making, 165
” large size, 216
” to center rods in, 285, 305
” band, 219
Lead, 99, 110
” use of, in brass, 90
Leaves of pinions, to polish, 445
Leclerre’s vibration counter, 395
Left-handed screws, to make, 320
Lever escapement, to examine, 391
Lift, to measure, 465
Lines, to connect up, 45
” ” draw parallel, 43
” ” subdivide, 43
Liquation, 92
Local time, 54
Locking stones, to make, 172
Longitude, value in time, 55
Lubrication of whetstones, 191
M
Magnetism, to remove, 403
Mainspring, setting up, 385
” to blue, 86
” ” make eye, 431
” ” reduce height of, 432
” ” select, 432
Malleability, etc., of steel, 70
Malleable bronze, 98
” castings, 61
” nickel, 100
Materials used in horology, 57
Measurement, exact, 38
” of angles, 26
” ” triangles, squares, etc., 26
” ” various solid bodies 28
Melting points, 110, 112
Mercury, 105, 110
” to purify, 106
Metals, 57
” to cement, 156
Methylated spirit, 132
Micrometers, 196, 270
Micrometer screw, 39, 48
Micrometrical dividing table, 48
Mill cutters for steel teeth, 347
Milling fixture, 258
Minute wheel, freedom of, 374
” ” to cut, 310
Mixed oils, 131
Mortar for making diamond powder 138
Motion work, to examine, 374
Motive force, effect of variations in, 402
Movement, to examine English and American, 389
Movement, to examine Geneva, 374
Muffle furnace, 201
N
Natural steel, 62, 65
Nickel, 99, 110
” movements, 100
” to surface, 147
” ” render malleable, 100
” silver, 100, 110
Nitric acid, 127
O
Oil, 128
” application of, 387
” necessary in keyless work, 393
” retention of, at center pivots, 378, 386
” ” ” on acting surfaces, 132
” tests of quality of, 129
” to secure permanency in, 130
Oil-cup chamferers, 281
Oil-cups, observations on, 282
” to polish, 153
Oilsinks, 131
Oilstone, 135, 190
Oilstones, circular, 191
Oilstone dust, to prepare, 137
Oriental chrysolite, 163
” ruby, 162
” sapphire, 163
Oxides of iron for polishing, 135
P
Paillard’s balance-springs, 108
Painting dials, 495
Palladium, 107
” balance-springs, 108
Pallets, 463
Pallet-opening calliper, 466
” stone, to alter, 464
” ” ” cement, 159
” ” ” make, 172
” ” ” move, 463
Pallets, verge, to open or close, 467
” ” ” measure, 466
Paper used in cleaning watches, 385
Parallel lines, to draw, 42
Parallelogram, 27
Pendulum, counting vibrations of, 394
” spring, _see_ Balance-spring.
” vibrations of, 460
Permanency in oil, to secure, 130
Perpendicular, to erect, 41
Petroleum, use for cleaning, 384
Pewter, composition of, 99
Physical properties of alloys, 108
Pickling dials, 488
Pinion, cannon, to tighten, 449
” hollow, to replace pivot of, 453
” leaves, to polish, 445
” riveting tool, 294
” to drift keyless, 297
” ” increase or decrease, 444
Pinions, etc., cutters for, 349
” high and low numbered, 460
” sizes of, 443
” to make, 442
Pivot-holes, cleaning, 382
Pivot polisher, 250
” to bush, 456
Pivots, balance, length of, 377
” ” form of, 400
” center, 378
” play of, 378, 452
” replacing broken, 453
” to polish mechanically, 454
” ” redress bent, 454
” ” turn, 183
Pivoting a cylinder, 454
Plate, watch, to make, 407
Plates, brass, to harden, 92
” for screw-making, 315
” to straighten, 504
Plating, gold, 124
” silver dials, 491
Platinum, 106
” balance-springs, 108
” to solder, 131
Pliers, 196
” hand-fitting, 288
Poise of balance, 401
Polish, black, on steel, 154
Polisher, form of, 155
Polishing brass, 149
” circular grooves, 428
” cylinder lips, tool for, 468
” escape-wheel teeth, 153
” flat objects, 302
” jewel-holes, 168
” machine for pinions, 445
” materials, 133
” pivots in lathe, 454
” powders, to prepare, 136
” ratchet teeth, 427
” sinks and oil-cups, 153
” steel, 153
” stones, Cadot’s, 136
Positions, timing in, 399
Post, to adjust, 415
Powers of numbers, 20
Precious stones, 161
” ” working in, 164
Preservation of health, 175
Prime numbers, 18
Proportion of numbers, 22
” ” balances, 401
Proportional compass, 37
Protractor, 33
Puddled steel, 62
Pulleys, 222
Pumice-stone, 135
Punch, centering, 285
” riveting, 198
Putty powder, 135
R
Radius defined, 24
Railway time, 55
Ratchet, to renew barrel-arbor, 425
” ” smooth, 140
” ” snail, 141
” teeth, to cut in lathe, 310
” to polish, 427
Ratio, 25
Receipts for watchmakers, 407
Red-stuff, 135
Re-facing burnishers, 198
Registering gauge, 273
Regulating a clock, 398
” ” watch, 396
Renewing files, 193
Repairing watches, 371
Resetting jewels, 300
Resin as flux for soldering, 117
Resist for use in gilding, 125
Retention of oil on acting surfaces, 132
Riveting stake and punch, 198
Rods, brass, to harden, 95
” to straighten, 504
Roller remover, 264
” to make duplex, 173
Roots of numbers, 20
Rose cutters, 349, 357
Rottenstone, 135
Rouge, 135
Rough steel, to clean, 75
Roughing files, 193
Round hole, to broach, 499
Rounding-up attachment, 259
” ” cones, 362
” ” cutters, to make, 331
” ” teeth by hand, 363
” ” tools, 330, 359
Rubitine, 134
Ruby, 162
” false, 163
” roller, to make duplex, 173
Rust, to remove and to prevent, 58
S
Sal-amoniac as flux for soldering, 128
Salts, 128
Sapphire, 163
Sapphirine, 134
Scale, to remove, from steel, 75
Scales used in drawing, 33
Scratch-brushing, 125
Screw dies, 315
” head sinking tools, 260
” ” to smooth, polish and slit, 143, 301
” micrometer, 39
” plates, to make, 316
” ” and taps, 315
” rapid mode of making, 326
Screws, double and treble threaded, 381
” left-handed, 320
” to blue, 86
” ” make internal and external, 315
” ” extract broken, 128, 262, 317
” tray for, 381
Sealing-wax as cement, 155
Seconds circle, to fix, 484
” ” ” make hole for, 484
Sector, 36
Semi-cylindrical drill, 245
Series of holes, to drill, 309
Set-hands arbor, to adjust, 451, 294
” nut, to make, 449
” square, to make, 422, 449, 500
Setting jewel-holes, 171
” ” cutters for, 236
Set-square, to center with, 286
Sharpening cutters, 237
Shear steel, 62, 66
Shellac as cement, 155
Shoulders, cutters for making, 236
” gravers for turning, 239
” to polish square, 155
” ” turn square, 183
Sight, to preserve, 175
Signs used in calculations, 19
Silver, 103, 110
” dial, to restore, 487
” German or nickel, 100, 110
” solders, 114
” solution for dials, 490
” for plating, to apply, 492
” ” ” ” prepare, 491
Sinks in watch plate, 131, 281
” to polish, 153
Sinking tools, 281
Slates, hone, 134
Slide rest, 233
” cutters, 236
” ” to sharpen, 237
” turning with, 234
Sliding tongs, 196
Smoothing brass wheels, 149
” metallic surfaces, 139
Snailing, circular, 141
” steel, 145
” tool for, 146
Soap, application of, 383
Solders for various metals, 113
” hard and soft, 113
Soldering, 112
” fluid, 118
” fluxes used in, 117
” iron, 118
” methods of, 115
” to clean jewelry after, 126
Solid content, measurement of, 28
” geometry, 23
” squares, 500
Specific gravity, 110, 111
” heat, 110, 111
Spelter solders, 114
Spinel ruby, 162
Spiral, to draw, 47
Split chucks, 224
Spotting, circular, 141
” machine, 141
Spring, balance, 473
Springs, to blue, 86
Square hole, to drift a, 502
” measurement of, 26
” root, 21
” set hands, to make, 422, 449, 500
” shoulders, to turn, 183
” to file by hand, 500
” winding, to renew, 430
Squares, solid and hollow, 500
” to make, 422, 449, 500
Staff gauge, 275, 277
” to straighten, 505
Stake, riveting, 198
Staking tool, 293
Star cutters, 348, 357
” wheel, to true, 417
” ” sink, to make, 410
Steel, 61, 110
” characteristics of good, 63
” drawn, 70
” drill blade for, 242
” influence of impurities on, 88
” maximum elasticity of, 82
” precautions in hardening, 79
” preparation of, 72
” to anneal, 72
” ” braze, 119
” ” clean rough, 75
” ” determine qualities of, experimentally, 66
” ” distinguish from iron, 58
” ” polish, 153
” ” restore, 59
” ” snail, 145
” ” smooth, 143
” ” temper, 81
” ” turn hard, 185
” ” whiten, 84
” wheels, cutters for, 347
Stem wind pinion, to drift, 503
” ” wheels, to make, 441
Stepping device, 227
Sterro, 99, 110
Stone, pallet, to cement, 159
Stones for polishing, Cadot’s, 136
” precious, 161
” to make pallet, 172
Stool, 190
Stopping barrel holes, 412
” pivot-holes, 456
Stopwork, proportions of Geneva, 416
” to examine English, 389
” ” examine Geneva, 374
Straight groove, to make, 312
Straightening rods, etc, 504
Stud index, hairspring, 280
Studs, to remove, 291
Subdivision of angles, 44
” ” circle, 52
” ” lines, 43
Sulphuric acid, 127
Surfaces, smoothing of metallic, 139
Surfacing nickel movements, 147
Synchrometer, Guilmet’s, 398
T
Tailstock, 247
Tap, to increase diameter of, 323
Tapping holes, various methods of, 323
Taps for screw-making, 317
” left-handed screw, 320
Teeth, forms of, 365
” of escape wheels, to test, 290
” ” lever escape wheel, to polish, 153
” ” to cut, 330
” precautions in cutting, 341, 346
” steel, to polish, 427
” to renew in wheel, 439
” ” round up, 363
” ” true, 440
Temper, as indicated by blueing, 87
Temperatures, determined by melting alloys, 82
” determination of furnace, 82
” of furnace, approximate, 73
” of temper colors, 82
Tempering steel, 82
Tightening cannon pinions, 293, 449
” hands, 294
” set hands arbor, 294
Time, 54
” standard, 55
” to ascertain true, 54
Timing in positions, 399
” watches and clocks, 394
Tin, 97, 110
” solders, 114, 115
” use of, in brass, 90
Tinning surfaces, 119
Tool, form of, for turning, 238
” for balance spring collet, 286, 474
” ” closing barrel holes, etc., 293
” ” drifting, 296
” ” flat polishing, 301
” ” measuring verge pallets, 466
” ” polishing cylinder lips, 468
” ” ” pinion leaves, 445
” ” ” pivots, 454
” ” resetting jewels, 299
” ” riveting pinions, 293
” ” snailing, 146
” ” spotting, 141
” ” tightening cannon pinions, 293
” ” ” hands, 293
” ” ” set hands arbor, 293
Tools, ordinary small, 260
” need of good assortment, 187
” screw head, 329
” for hand-turning, 238
” ” making jewels, 165
” ” rounding up teeth, 359
” ” sinking screw heads, 260
” ” watchmakers, 189
” to set in handles, 193
” ” sharpen turning, 237
” ” test accuracy of, 366
” ” ” escape wheels, 290
Tool set, 237
Tongs, sliding, 196
Topaz, 164
Tourmaline plates, 167
Tracing, 30
” from dial, 495
Train, play of pivots of, 378
Trains of watches, usual, 394
Transferring, 30
Traverse spindle grinder, 258
Triangles, 26
Tripoli, 135
Trueing a barrel, 412
” ” ” arbor, 429
” ” star-wheel, 417
” ” wheel, 440
Truth of tools, to test, 366
Turning sphere, tool for, 241
” by hand, 238
” tools, forms of, 238
” ” to grind, 237
” velocity in, 235
” with either hand, 186
” ” slide-rest, 233
Turpentine, use of, in drilling, 480
” Venice, as flux for soldering, 117
Tweezers, 196
” for removing studs, 292
U
Universal face-plate, 256
” head, 256,303
Unlocking pallets, to make, 172
Uprighting a barrel, 413
” of center wheel, 378
” tool, to test accuracy of, 367
V
Velocity in turning, 235
Verge pallets, to measure, 466
” ” ” open or close, 467
” to straighten, 505
Vernier, 37
” caliper, 278
” gauge, 278
Vibrations of balance or pendulum, 460
” to count, 394
W
Watch-glass, to reduce, 499
” hand holder, 287
” ” to blue, 86
” ” ” tighten, 293
” plate, to make, 407
” to de-magnetize, 403
” ” time rapidly, 394
Watches, to clean, 382
” ” put together, 385
” ” repair and examine, 371, 389
” usual trains of, 394
Watchmakers’ bench, 221
” receipts, 407
Water, annealing steel in, 73
” of Ayr stone, 135
Watered surfaces on nickel, 147
” surfaces, to produce, 139
Wavy surfaces, to produce, 139
Wax chucks, 157, 230
” to set objects in, 157
Weight of balance, 401
Wheel, cutters, 258
” ” or punch, 438
” ” tool for making, 354
” ” to make, 340
” cutting engine, 330
” ” ” to divide a rule on, 50
” ” ” to polish in, 427
” foot, 218
” mode of holding in cutting, 337
” teeth, to cut in lathe, 336
” tooth, to renew, 439
” to divide, 333
” ” make steel, 441
” ” mark crossings of, 298
” ” rough out, 435
” ” straighten, 504
” ” true, 440
Wheels, arbors for cutting, 337
” identical, 438
” observations on cutting, 346
” steel, cutters for, 347
” to ease depths of, 365
” ” polish brass, 149
” ” repair, 439
Whetstones, 190
White smoothing, 143
Whiting, 136
Wind furnace, 201
Winding square, to make, 422
” ” ” renew, 430
Wire-drawing plate, 298
” gauges, 272
Work-bench, arrangement of, 189
Y
Yellow copper or brass, 90
Z
Zinc, 89
THE WATCHMAKERS’ HAND BOOK.
PART I.
ARITHMETIC, GEOMETRY, DRAWING, ETC.
ARITHMETIC.
=1.= We often hear the theory advanced that in this country, at the
present day, it is not necessary to have a knowledge of arithmetic,
geometry, drawing, etc., because our interchangeable system of
manufacturing watches, makes all knowledge in these lines superfluous,
and that without any knowledge of arithmetic or geometry a man may
become a thorough master of watchmaking. This is a mistake that too
many of our young men make. The fact that the leading watch factories
of the United States have adopted the interchangeable system, of course
lessens the number of parts which the repairer will have to make and
fit, but it by no means alters the situation as regards the repairing
of foreign-made watches, nor even the changing of American watches from
key to stem-winders. Without a thorough knowledge of arithmetic and,
at least, an insight into the principles of geometry, no young man can
hope to become a first-class watchmaker in the true sense of the word.
Without these accomplishments he will be deprived of the pleasure of
reading understandingly the best literature of the day, the works of
those who are best fitted to impart knowledge to the members of the
trade.
With a knowledge of geometry he will be able to comprehend the works
of the best authors, to ascertain the dimensions of solid bodies, and
be in a position to apply the rules that form the basis of linear
drawing. Every watchmaker, worthy of the name, should be able to make
and understand the drawing of any machine, or of any horological
instrument. Many inventors, and even ordinary workmen, would avoid a
large amount of hard work, often useless, and occupying much time, if,
instead of at once putting an idea into practice with brass and steel,
they were able as a preliminary, to make for themselves a correct
design drawn to scale.
=2.= It is taken for granted that the reader is familiar with the rules
of arithmetic at least, and we will touch upon some points in algebra
and geometry that it will be well to mention. Should the reader have
no knowledge of arithmetic, algebra and geometry, we would advise
him to take up these studies during his leisure hours, using some of
the standard text books for that purpose.[1] Besides possessing a
knowledge of prime numbers, numbers which have no divisors but unity
and themselves, the watchmaker should be able to determine the greatest
common measure of several numbers, a rule which is of great importance
in calculating a train of wheels that is complicated.
We shall confine our attention to the methods of extracting square
roots and proportions, the rules for which may have been forgotten,
owing to their being less frequently employed than the more common
rules of arithmetic; they are of frequent use in horology.
SOME SIGNS EMPLOYED IN CALCULATIONS.
=3.= The sign of addition is an erect cross, +, called _plus_, and when
placed between two quantities it indicates that the second is to be
added to the first. Thus, 5 + 3 equals 8.
The sign of subtraction is a short horizontal line, -, called _minus_,
and when placed between two quantities it indicates that the second is
to be subtracted from the first. Thus, 8 - 3 equals 5.
The double sign, ±, is sometimes written before a quantity to indicate
that in certain cases it is to be added and in others it is to be
subtracted. Thus 5 ± 3 is read 5 _plus or minus_ 3.
The sign of multiplication, ×, when placed between two quantities
indicates that the first is to be multiplied by the second. Thus, 3 × 5
equals 15.
The sign of division is a short horizontal line with a point above and
one below, ÷, and when placed between two numbers or quantities it
indicates that the first is to be divided by the second. Thus, 6 ÷ 2
equals 3.
The sign of equality is two short, horizontal, parallel lines, =,
representing the words equal to. Thus, 6 ÷ 2 = 3.
Inequality is denoted by the angle >, the opening always being toward
the larger number or quantity; thus, in 12 + 7 > 14, the sign >,
indicates that the sum of 12 and 7 is greater than 14, and the whole
expression is read, 12 plus 7 is greater than 14. The expression 9 < 4
+ 7 is read, 9 is less than 4 plus 7.
A parenthesis, (), denotes that the several numbers or quantities
included within it are to be considered together, and subjected to the
same operation. Thus, (10 + 4) × 3 indicates that both 10 and 4, or
their sum, are to be multiplied by 3.
A horizontal vinculum, ------, placed over the numbers or quantities,
is frequently used instead of the parenthesis. Thus, @2 + 4 + 6@ × 7 is
equivalent to (2 + 4 + 6) × 7.
Division is more usually indicated by a line between the two figures,
the dividend being written above and the divisor below the line. Thus,
¹⁶⁄₈ indicates division, the same as 16 ÷ 8.
Algebra is that branch of mathematics in which the operations are
indicated by signs or symbols, and the quantities are represented by
letters.
The sign of ratio consists of two points like the colon, :, placed
between the quantities compared. Thus, the ratio of _a_ to _b_ is
written _a_ : _b_.
The sign of proportion consists of a combination of the signs of ratio.
Thus,: :: :. The first two and last two dots are read _is to_, while
the four in the middle are read _as_. Thus, if _a_, _b_, _c_, and _d_,
are four quantities which are proportional to each other, we say _a_ is
to _b_ as _c_ is to _d_, and this is expressed by writing them thus:
_a_ : _b_ :: _c_ : _d_.
POWERS AND ROOTS.
=4.= The power of a number is the product formed by successive
multiplication of the same number by itself. Thus,
2 × 2 = 4, the second power or square of 2.
2 × 2 × 2 = 8, the third power or cube of 2.
2 × 2 × 2 × 2 = 16, the fourth power of 2, etc.
An exponent is a number written above a quantity, at the right-hand, to
indicate how many times the quantity is to be taken as a factor, as
6^3 = 6 × 6 × 6.
The root of a quantity is a factor which, multiplied by itself a
certain number of times, will produce the given quantity. Thus, in the
above examples 2 is the square root of 4 and the cube root of 8.
The radical sign, √, indicates that the root of the quantity placed
under it is to be taken, and the index of the root is expressed by a
little figure placed outside of the bend. If a square root the index
figure is usually omitted.
√4 = 2 or ²√4 = 2 and ³√8 = 2.
=5. Extracting the square root of whole numbers.= [2]
I. Point the given number off into periods of two figures each,
counting from the units place to the left. For example, we wish to find
the square root of 399424, we point it off thus: 39,94,24.
II. Find the greatest perfect square in the left-hand period, and write
its root for the first figure in the required root; subtract the square
of this figure from the first period, and to the remainder bring down
the next period for a dividend. Thus:
39,94,24(6
36
--
394
III. Double the root already found, and write the result on the left
for a divisor; find how many times this divisor is contained in the
dividend, exclusive of the right-hand figure, and place the result in
the root and at the right of the divisor. Thus:
39,94,24(63
36
--
123 394
IV. Multiply the divisor thus completed by the last figure of the root;
subtract the product from the dividend, and to the remainder bring down
the next period for a new dividend. Thus:
39,94,24(63
36
--
123 394
369
---
2524
V. Double the right-hand figure of the last complete divisor for a new
divisor, and continue the operation as before. Thus:
39,94,24(632
36
--
123 394
369
---
1262 2524
2524
PROPORTION.
=6.= It is often convenient to express the relations of qualities in
the form of a proportion and from the proportion derive an equation.
Ratio is the quotient of one number divided by another. Thus the ratio
of 30 to 6 is ³⁰⁄₆.
=7.= Proportion is the equality of ratios: Thus if ³⁰⁄₆ = 5 and ⁴⁰⁄₈ =
5 then we may state that ³⁰⁄₆ = ⁴⁰⁄₈ or the proportionality is usually
expressed (=3=) thus:
30 : 6 :: 40 : 8
and this constitutes what is called a geometrical proportion, and 30
and 8 are called the extremes and 6 and 40 the means.
=8.= The product of the extremes is always equal to the product of the
means. Thus: 30 × 8 = 6 × 40 = 240. Hence it follows that if we only
know three terms we can always determine the fourth, or unknown term,
which is usually represented by the letter _x_. Thus in the proportion
12 : 3 :: 16 : _x_
we find the product of the means, or 3 × 16 = 48; this product divided
by 12, the known extreme, gives us the value of _x_, or the unknown
extreme, as equalling 4.
=9.= If we know the two extremes and only one of the means the same
rule is applied. Thus in the proportion
20 : 5 :: _x_ : 25,
we have: 20 × 25 = 500. ⁵⁰⁰⁄₅ = 100, the value of _x_.
ELEMENTS OF PRACTICAL GEOMETRY.
=10.= The object of geometry is to measure the extent of bodies. A body
has three dimensions, _length_, _breadth_ and _thickness_, and one of
these latter is sometimes termed _weight_ or _depth_.
Either dimension taken by itself is measured by a straight line.
When the extent of a body is expressed by combining any two dimensions,
it is termed _area_ or _surface_, and when three are employed we obtain
the solid measure or _volume_.
_Plane_ geometry only takes cognizance of figures situated in one plane
or surface, and therefore only possessing two dimensions; _solid_
geometry, however, regards bodies as having all three dimensions.
Two lines are parallel when their distance apart is the same at all
points. The same is also applicable to parallel planes.
Two lines or planes meeting each other will form an _angle_. The point
at which they meet or intersect is termed the _apex_ or _summit_ of the
angle.
A straight line is _perpendicular_ or _at right angles_ to another
straight line, or to a plane, when all the angles which it makes with
that line or plane are equal.
A _circumference_ of a circle is a curved line _l c d f_ (fig. 1,)
such that all its points are equally distant from an internal point,
_o_, termed the _center_. The _circle_ is the space enclosed by the
circumference.
It will be noticed that in geometry these two words are distinguished,
although they are frequently referred to as identical. Thus, the rim of
a wheel or balance is generally termed a circle.
Two circles (_l c d f_ and _b r a_, fig. 1,) described from the same
center are said to be _concentric_. When their centers do not coincide
they are called _excentric_ with regard to one another.
Any portion of a circumference, such as _f n d_, is termed an _arc_ of
the circumference, or, more commonly an _arc of a circle_.
A _chord_ is a straight line, _f d_, which unites the two extremities
of an arc. When the chord passes through the center of a circle it is
termed a _diameter_.
The _radius_ of a circle or circumference is a straight line drawn from
the center to the circumference; and all the radii that can be thus
drawn are equal. A diameter is, then, always double the radius, and,
conversely, the radius, is always half the diameter.
A _tangent_ is a straight line that only touches a circumference at one
point, as _g l_ (fig. 1); whereas a _secant_ cuts the circle, as _i j_.
A circumference is assumed to be divided into 360 equal parts, termed
_degrees_. The degree is subdivided into sixty equal parts, or
_minutes_, and the minute into 60 _seconds_. These are respectively
symbolized by the marks ° ′ ″ placed at the right-hand top corner of
the figure.
Such an expression as 18° 30′ 15.5″ would, then, be read 18 _degrees_,
30 _minutes_, and 15.5 _seconds_.
=11.= =Ratio of the circumference to the diameter.= The diameter of
a circle is to the circumference as 7: 22; or, employing decimal
fractions, as 1: 3.14159 (a number which, in algebra, is always
represented by the Greek letter π.)
[Illustration: _Fig. 1._]
Knowing a diameter (D), the circumference, _x_, can be ascertained from
the proportion:—
1 : 3.14159 :: D : _x_.
Knowing a circumference (C), the diameter, _x_, can be determined from
the proportion:—
3.14159 : 1 :: C : _x_.
The latter proportion will also give the value of the radius, which is
half a diameter.
=12.= The _superficial area of a circle_ is equal to the circumference
multiplied by half the radius, or to the square of the radius
multiplied by 3.14159.
A _sector_ is the circle enclosed between an arc and two radii bounding
it, as _b_ O _r k_ (fig. 1.)
The area or surface of a sector can be ascertained by multiplying the
length of the arc by half the radius.
A _segment_ of a circle is the portion intercepted between an arc and
its chord, as _f d n_ (fig. 1.)
The surface of a segment, as _b k r s_, can be obtained by subtracting
from the area of the sector O _b k r_, the area of the triangle, _b r_
O (=15=).
=13.= _Ring._ To determine the surface of a flat ring, the area of the
inner circle must be subtracted from that of the outer circle; in other
words, take the difference between the areas of the two circles that
fix the inner and outer diameters of the ring.
The area of a flat ring can also be calculated by adding together the
internal and external diameters; then multiply the number so obtained
by their difference and by the decimal fraction 0.7854 (that is,
3.1415/4). The product will be the required area.
=14.= _Angles and their measurement._ When two lines meet one another,
they form an angle, as we have already seen. If we take the apex as the
center of a circle, the number of degrees intercepted between the two
straight lines gives a measure of this angle.
The angle measured by a quarter of a circumference, or 90°, is termed a
_right angle_.
An _obtuse_ angle is greater than a right angle, and an angle that is
less is termed an _acute_ angle.
=15.= =Triangles, squares, etc., and their measurement.= The triangle
or plane area enclosed within three straight lines joined two and two
together (A, B, C, fig. 2,) is said to be _rectangular_ when one of its
angles is a right angle; it is _equilateral_ when the three sides are
equal, under which circumstances the three angles are also equal; and
_isosceles_ when only two sides are of equal length.
The sum of the three angles of a triangle is always equal to two
right angles. If only two of the angles are known, it is thus easy to
determine the third.
_Similar_ triangles are characterized by the fact that their homologous
sides (that is, the sides opposite to equal angles) are proportional.
_Peculiarity of the right-angled triangle._ The square described on the
longest side, termed the _hypothenuse_ (B, fig. 2,) is equal to the
sum of the squares described on the two other sides. Hence, it follows
that, if the lengths of the two shorter sides are known, that of the
hypothenuse can be ascertained by extracting the square root of the
number formed by adding together the squares formed on these two sides
(=5=).
[Illustration: _Fig. 2._]
If the hypothenuse is known and one of the shorter sides, the third
can be determined by extracting the square root of the number formed
by subtracting the square of the known side from the square of the
hypothenuse.
The _surface of a triangle_ is determined by multiplying one of the
sides by half the perpendicular height of the angle opposite to this
side.
=16.= The _surface of a square_ or of an oblong or _rectangle_ (_a b
c d_, fig. 3) is equal to the product of the base multiplied by the
height.
The sum of the squares described on the four sides is equal to twice
the square described on a diagonal. This diagonal divides the rectangle
into two equal rectangular triangles.
=17.= The _surface of a parallelogram or lozenge_, a plane figure with
four sides, opposite pairs of which are parallel (_c f g d_ and _c i
j d_, fig. 3,) is equal to the product of one side multiplied by the
perpendicular height of the figure.
[Illustration: _Fig. 3._]
The sum of the squares described on the four sides of a parallelogram
is equal to the sum of the squares described on the two diagonals.
=18.= =Measures of various solid bodies.= The volume of a cube of
parallelopiped (that is, a body bounded by six four-sided figures,
every opposite two of which are parallel) is obtained by multiplying
the surface of the base by the height.
The _volume_ of a straight cylinder is the product of the surface of
the circle which forms its base into the height of the cylinder.
The _area_ of the curved surface of a cylinder is obtained by
multiplying the circumference of the circle forming its base by the
height.
The _volume_ of a tube or cylindrical ring of rectangular section, such
as the arbor-nut of a barrel, or the rim of a circular balance, etc.,
is equal to the product of the plane surface of its base (=13=) into
its height.
The _volume_ of a _right cone_ or of a _regular pyramid_ is the product
of the base into a third of the height.
The _surface_ of a _sphere_ may be determined by multiplying the square
of the diameter by 3.1416 (=11=).
The _volume_ of a sphere is equal to this surface multiplied by a third
of the radius.
GEOMETRICAL DRAWING.
=19.= An elementary knowledge of the art of drawing, an ability to
represent the outlines of objects by simple lines, is of the first
importance to the watchmaker.
Such a design is obtained by projecting on to one plane all the visible
points of the object represented.
Projection on a vertical plane gives an _elevation_; the object is
looked at from one side.
Projection on to a horizontal plane produces a _plan_; the object is
observed from above, thus giving a bird’s-eye view.
The projection of a point on a vertical or horizontal plane is the foot
of the perpendicular, from the given point on to the plane. Assume the
line _n m_ (fig. 4), to be fixed in space; its horizontal projection
will give _c d_, and its vertical projection, _r s_.
[Illustration: _Fig. 4._]
_Miscellaneous details._ When one portion of the object to be
represented is found to pass behind other pieces so that it cannot be
seen, the continuation is frequently indicated by dotted lines.
Surfaces that are situated in planes one behind the other are shaded,
the more deeply according as they are farther back. This shading
is produced by a number of parallel lines which may be vertical or
horizontal.
Parts that are in relief are indicated by projected shadows, or by
increasing the thickness of a line that would cast a shadow.
In order to distinguish the several shadings or to emphasize the lines
by which they are separated, it is a very usual, though not invariable
practice to assume the light to be coming from the left-hand upper
corner.
When drawing a square in relief, such as _a b c d_ (fig. 3), the lines
_c d b d_, will be made darkest; but if it is a recess, the lines _a
b_, _a c_ should be brought into prominence by means of dark lines.
[Illustration: _Fig. 5._]
These several directions will be found useful when a hole, any cavity,
a pin, a round object etc., has to be depicted, as in fig. 5. As a
general rule, the thick lines should indicate the position at which a
shadow would form, the light being assumed to fall on the drawing in
the manner indicated above.
A _section_ shows a body as it would appear if cut in two, and one
portion removed in order to expose the interior, as in fig. 6. A
section is indicated by a series of parallel lines drawn close together
and at an inclination of about 45° to the vertical.
[Illustration: _Fig. 6._]
In order to leave more room for important details, or to show objects
that are situated behind, a piece is often broken off by an irregular
line, as shown in that drawing.
Lines formed by a series of detached points sometimes serve as a means
of associating several figures representing the same object looked as
in different directions.
=20.= =Tracing and transfering.= These two operations are resorted to
when it is required to obtain one or more copies of a picture or design
already drawn.
Tracing consists in laying a piece of tissue or other translucent paper
over the drawing and copying it by following over the lines that are
visible with a pencil. Or ordinary paper can be used for the purpose,
providing it is not too thick, if the picture be placed against the
pane of a window or, what is more convenient, on a sheet of glass used
as a desk and illuminated from below. When either sheet of paper is too
thick to allow sufficient light to pass, one or other of the methods of
transfering indicated below must be resorted to.
=21.= This operation consists in reproducing a tracing on a separate
sheet of paper or on metal that is to be engraved. Either of the
following methods may be adopted:
1. The picture to be transferred is fixed to a table or drawing board
if tracing paper is to be used, or to a sheet of glass if only ordinary
paper is available. The lines are then traced with a black lead pencil
that must not be too hard. When this is finished it is laid, face
downwards, on a sheet of white paper, taking care that both sheets are
so fixed that they shall not slip. Apply pressure to the upper surface
by tapping with a small pad made on purpose and, at the same time,
gently rubbing. Experience will very soon show how hard the pad should
be. Now remove the tracing, still taking care to avoid any slipping,
and a faint reproduction of the design will be found on the lower sheet
of paper. It is only necessary to follow over the lines with India ink.
The figures will be reversed but a transfer with it in the original
direction may be obtained by inverting the picture and laying it on
glass so as to make a reverse tracing.
2. Lay the picture on a desk or drawing board and trace it with ink
on a very transparent sheet of paper. When the ink is dry, invert the
tracing and blacken the back with a No. 2 pencil. Now lay the tracing,
with the ink side uppermost, on a sheet of clean paper, taking care to
avoid slipping, and go over the several lines with an agate or metal
style, avoiding excessive pressure on account of the risk of tearing
the paper. On removing the upper sheet an impression will be found not
reversed. Go over all the lines with India ink and clean the paper with
India-rubber or stale bread.
_Observations._ The choice of paper and pencil is not a matter of
indifference. All kinds of paper do not receive an impression equally
well, neither do all pencils transfer with equal facility. The Faber
pencil No. 3, will generally be found best suited to such work.
In preparing drawings which you desire to preserve, as drawings of
escapements, etc., a good quality of light weight bristol board will
be found more desirable than the best drawing papers. White wedding
bristol, about two-ply in thickness, answers admirably, and India ink
lines drawn upon it will not spread as they often do on drawing papers.
The prepared liquid India inks now on the market are superior to any
you can prepare by grinding the sticks.
=22.= =To transfer an engraved design.= This method is available when
it is desired to obtain an impression, for example, of the engraved
surface of a watch case.
Procure some of the inks used by copper-plate engravers, or, in its
absence, ordinary stencil ink may be used. Taking a small quantity on
the end of the finger, tap it on the surface of a glass plate, in order
that the ink may be distributed, leaving only a small quantity evenly
spread over the finger: tap with the finger thus prepared over the
watch case long enough to make sure that all the surface in relief has
received some ink; take a piece of writing paper and, after slightly
moistening it, spread it over this surface. Lay above this a piece of
paper folded in four and pass over it in all directions any round body,
such as a small tool handle, and with some pressure; then raise the
papers without allowing them to slide.
If the operation has been carefully performed a very clear impression
will thus be obtained of the engraved surface. The relief will be black
and the hollows white, but, of course, the figure is reversed like
that in a looking-glass. If required in the right direction it must be
traced through to the other side of the paper.
DRAWING INSTRUMENTS.
=23.= It is needless here to describe the rule, set-square, =T=-square,
bow-compass, etc., as every one knows them.
_To verify the accuracy of a rule._ On a perfectly flat smooth surface
carefully draw, with the rule in question, a fine straight line. Then
turn the rule over, hinging it as it were on the line just drawn; if
quite straight the edge of the rule will exactly coincide with the
line, in this new position, throughout its entire length. Each edge
should be thus examined.
_To verify the accuracy of a set-square._ Having fixed an accurate
rule on a smooth surface, place one edge of the set-square against it,
and draw a line along the edge perpendicular to the rule; then, having
turned the set-square, hinging it on the line just drawn, bring it
against the rule and along the line. If the square is true the edge and
line will coincide throughout their length.
=24.= =The Protractor.= Fig. 7 represents a common form of this
instrument. It is made of horn, or, if of metal, the inner portion is
cut away, leaving only a base and a semicircular arc, which is divided
into 180 equal parts or degrees; a complete circle would therefore
consist of 360 such degree. The point indicating the center of the arc,
should be very small in order to facilitate the exact setting of it at
the apex of an angle.
[Illustration: _Fig. 7._]
When an angle has to be drawn with accuracy, the protractor is
unsuitable; it will be better to adopt one of the methods described at
paragraph =37=, or trigonometrical methods.
=25.= =Drawing scales.= When an object is represented by a drawing, if
the dimensions are the same as those of the object itself, or, rather,
as they would project on to a horizontal or vertical plane, the drawing
is said to be full size; but the object is generally represented either
on an increased or diminished scale, which is defined, the proportions
between all the parts being still, however, maintained the same.
With a view to avoid the many calculations that such a change would
involve, it is usual to employ drawing scales. The following notes will
sufficiently explain their construction and use.
Let it be required to reproduce a large drawing on a small scale, in
such a proportion that the dimensions are reduced in the ratio of 10 to
1.
[Illustration: _Fig. 8._]
Take a straight line of indefinite length, _a b_, fig. 8, and mark out
on it spaces equal to _a_ 1, which represents any measurement taken on
the original object; at _c_, the 10th division, draw a perpendicular,
and on it measure _c g_ equal to _a_ 1, or one-tenth of _a c_ and join
_a g_.
Through the points indicating the divisions into tenths draw lines
parallel to _c g_, and you will thus have a series of triangles, _d
a_ 1, _d′ a_ 2, _d″ a_ 3, etc., similar to the triangle _g a c_. In
virtue of a well-known property of such triangles (=15=), _d_ 1 will be
one-tenth of _a_ 1; _d′_ 2 one-tenth of _a_ 2; and so on.
Thus, if a measurement taken on the object, or on a large drawing, is
equal to _a x_, it will only be needful to turn the compass on the
point _x_ as a center, and to observe accurately the perpendicular
height, _x z_, to ascertain the corresponding measurement on the
reduced scale.
Such a scale can be employed to measure meters and decimeters, or feet
and inches (but in this latter case, it would have been necessary to
mark off 12 instead of 10 divisions from _a_). Since _a_ 1 might be
made to represent one metre; _a_ 2, two meters, etc., in virtue of
the principle of the triangle already referred to, _d_ 1 will be the
tenth of _a_ 1, and will therefore represent a decimeter; _d′_ 2 will
represent 2 decimeters, etc. The length required to represent, say 5.3
will be ascertained by taking the distance _a_ 5, to which the distance
_d″_ 3 is added. Similarly 6 feet 2 inches would be given by _a_ 6, to
which _d′_ 2 is added on a 12-division scale.
=26.= The following description of one of these decimal scales, which
is engraved on metal or ivory, and often included in cases of drawing
instruments, will suffice to enable any one to construct a scale on
this principle, that goes to a still further degree of accuracy,
measuring, for example, meters, decimeters and millimeters, or yards,
feet and inches.
[Illustration: _Fig. 9._]
Let A B, fig. 9, be a flat rectangular rule, divided throughout its
length by parallel equidistant lines into ten strips. At right angles
to these are the lines _o o′_, _a a′_, etc., separated from one another
by a distance of one centimeter (doubled in the drawing in order to
make the details more clear.) The first centimeter is subdivided along
the two edges, A _o_, _n′ o_, into 10 equal parts or millimeters, and
the division, _o_, on the upper edge is joined by an oblique line with
the 1 on the lower edge, and the others by parallel oblique lines as
shown in the figure. Thus _c i_ will be one-tenth of a millimeter, _s
j_ two-tenths, and so on.
If the compass is opened so as to reach from _x_ to _z_, it will
be seen that it covers a space of 16 millimeters and 2-10ths of a
millimeter, for there are one large division (or 10 mm.), 6 smaller
divisions (or millimeters) plus a fraction of a millimeter equal to _s
j_ or 2-10ths of a millimeter.
=27.= =Sector.= When it is required to reduce the scale of a drawing,
subject to the condition that the dimensions shall be all diminished in
the ratio of two given lines, we may state the problem thus:
The longer of the two given lines is to the shorter, as any given
dimensions of the old drawing is to _x_. The value of _x_ thus
determined will be the corresponding dimension of the new figure.
Such a rule of three proposition would involve a considerable amount of
work, and the required result can be arrived at with greater facility
by the geometrical methods which forms the basis of the scale just
described, or, better still, by using the sector shown in fig. 10. It
consists of two brass or ivory legs hinged about a center _m_ which is
at the apex of the angle _n m c_ formed by two straight lines similarly
divided into equal parts.
[Illustration: _Fig. 10._]
It is employed as follows: Let us assume that a drawing has to be
reduced in the ratio of the line A to the line B; set off the length
A along _m n_, and suppose its extremity to be at _s_, where division
number 5 occurs. Open a compass to a distance equal to B, and placing
one point on _s_, open the two legs of the scale until the second point
coincides exactly with the corresponding division _t_, that is, with
the 5 on the other leg, _m c_. Maintaining the scale open to this
amount, it is only needful, after measuring a distance on the original
drawing or object, to set it off along _m n_, and to measure the
distance between its extremity and the corresponding point on the other
leg; this distance will be the dimension on the reduced scale.
=28.= =Proportional compass.= This consists of two equal stems
terminating with points, fig. 11. They are cut through for a portion of
their length, and provided with a slide forming a hinge, that can be
clamped by a screw _a_ in any position. Graduations on the two slots
and a mark on the slide indicate in what position of the slide _a_,
the length _a b_ (equal to _a g_) is equal to ½, ⅛, ¼, etc., of _a d_;
and thus show what is the ratio of _g b_ to _c d_, a ratio which is
independent of the extent to which the arms are opened.
[Illustration: _Fig. 11._]
=29.= =The vernier.= The vernier consists of a small graduated slide
which is adapted to a graduated rule or circular arc with a view to
ascertain the value of small fractional parts of the divisions marked
on the rule or arc.
Let A B, in fig. 12, be a rule divided into millimeters (the
proportions are enlarged in the drawing so as to avoid confusion among
the lines), and let it be required to determine a length to within the
tenth of a millimeter.
As the measurement is required to the tenth, take ten less one or nine
of the divisions of the scale; they will extend from O to IX, and this
represents the acting length of the vernier.
Subdivide the vernier into ten equal parts; it is manifest that each
graduation of the vernier differs from the original subdivisions of
the rule by 1-10th of a graduation of the latter. In other words, unity
on the vernier is equal to 9-10ths of unity on the rule.
[Illustration: _Fig. 12._]
When the rule and vernier are placed as shown in fig. 12, so that the o
on both scales coincide, the successive divisions on the rule (marked
with Roman numerals for distinction) will be progressively more and
more in advance of the corresponding divisions on the vernier in the
following proportion:—
The marks I and 1 are 1-10th apart; the marks II and 2, 2-10ths; III
and 3, 3-10ths; and so on, the mark X being 10-10ths, or one complete
division in advance of 10, this division being a unit on the scale.
Thus if the vernier is caused to slide along the edge of the rule, when
1 coincides with I the vernier has advanced 1-10th; when 2 coincides
with II, it has advanced 2-10ths; and so on.
Let it be required to determine the distance P _d_, fig. 13. The
division 6 on the vernier coincides with a division of the scale; hence
it follows that the extremity _d_ of the vernier is at a distance of
6-10ths millimeters from III, the next division of the scale to the
left. The distance between P and _d_ is thus 3.6 millimeters.
[Illustration: _Fig. 13._]
With a vernier showing tenths, if two consecutive divisions of the
vernier fall between two divisions on the rule, and there does not
appear to be a tendency towards one side more than towards another,
even when observed with a strong glass, it is possible to take an
approximate reading to the twentieth.
[Illustration: _Fig. 14._]
In measuring circular arcs a curved vernier is used in place of a
straight one, and its graduations are made to correspond with those on
the circle as shown in fig. 14.
=30.= =Micrometer screw.= By employing a micrometer screw it is
possible to measure infinitesimal amounts, but the screw must be
perfectly accurate, and must work without appreciable backlash or loss
of time.
[Illustration: _Fig. 15._]
Assume V, fig. 15, to be such a screw, having a pitch of 1 millimeter.
It will advance by this amount with each complete rotation.
To the head of the screw is attached a disc of such a size that its
rim can be divided into a number of equal parts, say a hundred. These
graduations may be marks on the edge or notches cut in it when an index
is required to stop in them; but the index is less frequently met with
than a simple divided straight-edge almost in contact with the disc.
The divisions round the disc are numbered in ascending order as the
points _c_ and _a_ separate, so that zero comes under the index or rule
when these points are in contact. Readings of the numbers will thus
afford a measure of the displacement of the point of the screw.
When the disc is rotated the point a will move towards or from _c_
by 1-100th of a millimeter for each division passing under the
straight-edge, and one millimeter for each complete rotation. It is
thus possible to obtain the dimensions of an object when it enters
without play between the two jaws to within an error of about 1-100th
of a millimeter if the instrument is accurately made.
If, instead of passing the object between the two jaws, it is gripped
by them, the measurement will be less exact, as no account is taken of
the pressure exerted and of the elasticity. (=44.=)
GEOMETRICAL DRAWINGS.
=31.= =Sketches.= It is advisable from an early age to accustom oneself
to make rapid freehand sketches of objects as they present themselves
to the eye. Such a sketch will help in the preparation of a more exact
drawing, which involves a knowledge of the several geometrical methods
given below.
A drawing may be transferred, reduced or enlarged as follows:
Draw across the original picture a number of equidistant vertical and
horizontal lines, forming perfect squares, and number the two sets of
lines in succession. Then draw a similar series of lines on a clean
sheet of paper, setting the lines at an equal, less or greater distance
apart, and copy in succession the parts of the figure that are enclosed
within the several squares.
As it is not always possible to draw lines across a figure, they may
be replaced by a frame carrying fine threads or wires stretched in the
two directions. The frame is laid over the original drawing, which can
then be copied, as above explained, on a sheet of paper divided into
squares (fig. 16).
[Illustration: _Fig. 16._]
The frame may, moreover, afford assistance in the drawing of solid
objects. Having placed it above or in front of the object and
in contact with it, copy on to the sectional paper the contents
of each corresponding square, taking care to look at the object
perpendicularly. With a little practice, and by placing the eye in
the correct position and always at the same distance from the frame
(a distance which may be regulated by a glass), a sketch in fair
proportion may easily be obtained.
[Illustration: _Fig. 17._]
=32.= =To erect a perpendicular on a straight line.= Either the compass
or a set-square can be employed; the use of the latter instrument is so
simple that no further reference need be made to it. Assume _a_, fig.
17, to be the point in the line _n m_ at which a perpendicular is to be
drawn. On either side of _a_ measure off equal distances _a n_, _a m_;
from _n_ and _m_, with a radius about equal to the distance _n m_, draw
two circular arcs cutting one another. If their point of intersection
_b_ be joined to _a_, the line _a b_ will be the required perpendicular.
[Illustration: _Fig. 18._]
=33.= =To erect a perpendicular at the extremity of a line.= From the
extremity _c_, fig. 18, mark off four equal parts towards _s_. From
_s_, with a radius equal to five such parts, describe a circular arc,
and from _c_, with a radius of three such parts, describe another
arc cutting the first at _d_. The line joining _c_ and _d_ will be
perpendicular to _s c_.
For the square of 5 is 25, and this is equal to the square of 4 or
16 plus the square of 3 or 9. Thus the triangle _s c d_ must be
right-angled (=15=).
[Illustration: _Fig. 19._]
Or the following method may be adopted: With any center _i_ and radius
_i g_ (fig. 19), as large as possible, describe a circumference passing
through _g_. From the point _p_, where the circle cuts the line, draw
the diameter _p i h_. If the point _h_ be joined to _g_, it is the
required perpendicular; for, by a property of the semicircle, the angle
_h g p_ is a right angle.
[Illustration: _Fig. 20._]
=34.= =To let fall a perpendicular on a straight line.= In order to
let fall a perpendicular from the point _a_ on to the line _b c_ (fig.
20), describe from _a_ as a center, a circular arc sufficiently large,
cutting the straight line in two points, _b_ and _c_. From these two
points, with the same opening of the compass, draw on the under side of
the line two arcs that intersect. The point of intersection _o_ joined
to _a_ gives the required perpendicular.
[Illustration: _Fig. 21._]
=35.= =To draw parallel straight lines.= Having fixed a good
straight-edge over the drawing, as many parallel lines as are required
may be drawn with the aid of a set-square which is caused to slide
along the rule. They will be vertical, horizontal or inclined,
according to the position of the rule, which must be set exactly
perpendicular to the direction in which the parallel lines are to be
drawn (fig. 21).
[Illustration: _Fig. 22._]
_To draw, from a given point, a line parallel to a given line._ Let _d_
be the given point, and _a b_ the given line (fig. 22). From _d_ draw
the circular arc _a c_, and from _a_ where it cuts _a b_, with the same
radius describe the arc _d b_. From _a_ set off on _a c_, a distance
equal to _d b_. The line joining _d_ and _c_ is the required parallel.
[Illustration: _Fig. 23._]
=36.= =To subdivide a line into equal parts.= Let it be required to
divide the line _p v_ (fig. 23), into five equal parts. Draw a line _p
q_ inclined at any angle, and mark off on this line five equal parts of
any length; join _q_, the extremity of the five lengths, and _v_, and
through the points _a_, _b_, _c_, _d_, draw lines parallel to _q v_. In
virtue of a property of similar triangles these lines will divide _p v_
into equal parts. It is advisable that the lines _p v_ and _p q_ should
not differ very considerably in length, as, otherwise the inclination
of the parallel lines to _p q_ will render it difficult to observe the
exact point of intersection.
[Illustration: _Fig. 24._]
_To divide a line into proportional parts._ The proposition can be
solved in a similar manner. Let it be required to divide a line _t r_
(fig. 24), into two sections that are to one another in the proportion
of 5 to 3. On _t s_ mark off a series of equal parts given by the
addition of these numbers together, that is 8; and join the last point
_s_ to _r_. Then draw through _c_, the fifth division, a line parallel
to _s r_. This line _c d_ will cut _t r_ into two parts, which are to
one another in the proportion of 5 to 3.
By an analogous construction a fourth proportional can be graphically
obtained, as already indicated in articles =25=-=27=.
=37.= =To construct an angle equal to a given angle.= The angle may be
measured by means of the protractor (=24=), which then enables us to
draw a similar angle; but greater accuracy is obtainable by using the
compass.
[Illustration: _Fig. 25._]
Let it be required to construct at _m_ on the line _m p_ (fig. 25), an
angle equal to _b a d_. With as large a radius as possible, draw from
the points _a_ and _m_ the arcs _b d_ and _n p_. Measure the distance
_d b_ and mark it off with the compass from _p_ on the arc _p n_. A
line drawn through _m_ to the intersection of the two arcs will give
the required angle equal to _b a d_.
=38.= =To subdivide an angle into 2, 4, or 8 equal parts.= In addition
to the use of the protractor, the following graphic method is often
given in works on geometry.
[Illustration: _Fig. 26._]
An angle _e f g_ being given (fig. 26), from its apex _f_ as a center
describe the arc _e g_, and from its two points of intersection with
the sides, with a radius greater than half their distance apart, draw
two short arcs cutting each other at _s_. A line drawn from _f_ through
the intersection _s_ will divide the angle into two equal parts.
If four divisions are needed, repeat the process on the two angles _s f
e_, _s f g_, and so on for a further sub-division.
The line that divides the angle into two equal parts will also bisect
or divide into two equal parts the chord and the arc _e g_.
[Illustration: _Fig. 27._]
=39.= =To find the center of a circle or of a circular arc.= Take on
the circumference, or on the arc, three points _b c r_ (fig. 27).
Join _b_ to _c_ and _c_ to _r_. At the middle point of each of these
lines[3] erect a perpendicular. The point of intersection of these
perpendiculars is the required center.
A similar method should be resorted to when it is desired to describe a
circle passing through three given points.
[Illustration: _Fig. 28._]
=40.= =To connect up or associate lines.= In order to join up a
straight line, such as _i j_ (fig. 28), with the curve _l p_, erect a
perpendicular at _j_, and through the middle point of a chord, _l p_,
draw a second perpendicular cutting the first in _k_. This point will
be the center from which the curve uniting the two lines should be
struck.
[Illustration: _Fig. 29._]
To unite a curve _a b_ (fig. 29), with another curve, _c x_ or _c
z_, at the point _c_, first find _o_, the center of the curve _a b_,
draw the line _a o_, continuing it beyond the center; join _a_ and
_c_, and erect a perpendicular at the middle point of this chord. The
intersection of this perpendicular with _a o_, produced if necessary,
should be taken as the center for a curve uniting _b a_ with _c_.
[Illustration: _Fig. 30._]
To join up two lines inclined to each other or parallel lines of
unequal length, such as _a r_, _b s_, fig. 30, draw midway between the
two another line, _z d_; join the two extremities _r_ and _s_, and from
these points let fall perpendiculars _r i_ and _s c_; then from _d_
draw a line perpendicular to _s r_. The point _o_ thus obtained will be
the center of the arc _r d_, and _c_ will be the center for _d s_.
=41.= =To describe an ellipse.= Let _a b_ (fig. 31), be the major axis
of the ellipse; divide it into three equal parts, and from the two
points, _c_ and _i_, at which it is divided, with a radius equal to _i
c_, draw (in pencil) two circles, intersecting in the points _x_ and
_z_. Through these points draw the lines _x i g_, _x c h_, _z i f_, _z
c d_.
With the center _z_ describe the arc _d f_, and from _x_ draw _h g_;
the ellipse will be completed by the two arcs, _f b g_, _d a h_, of the
primitive circles.
[Illustration: _Fig. 31._]
If it be required to describe an ellipse that shall have a shorter
minor axis, divide the major axis into four equal parts, thus obtaining
three points of sub-division. With each point as a center and with a
radius equal to one of the spaces describe circles. Those to the right
and left will determine the extremities of the ellipse, and the central
circle will intersect the minor axis in two points which must be taken
as centers for describing the top and bottom portions of the figure.
[Illustration: _Fig. 32._]
When the length of the long and short axes are given, proceed as
follows (fig. 32): From the center _a_, where they intersect at right
angles, mark off the distances _a n_, _a o_, equal to the difference in
the length of two semi-axes. Join _n o_, and add one half of _n o_ to
_a o_ measured in the direction of _a v_, thus obtaining the point _k_;
with the radius _a k_ describe a circle. On this circumference will lie
the four centers; _k_ for the arc _r u s_, _m_ for the arc _p v q_, _t_
and _i_ for the short arcs _q j s_, _p e r_.
The figures obtained by the methods here given closely resemble the
ellipse, but are not of the strict mathematical form. It is well
to acquire some facility in drawing ellipses, for the projection
of a circle on a plane, when the two are neither parallel nor
perpendicular, is an ellipse, and one often has occasion to describe it.
=42.= The following may be added as a mode of describing an ellipse:
The major axis and the two foci (points in this axis) being known, fix
two pins in these foci. Then tie a piece of string into a loop and
place it over the pins; stretch it with a pencil, the point of which
is on the paper, and on moving this around in a circular direction,
the string being maintained stretched, an ellipse will be described.
When the string is so stretched that it lies along the major axis, the
length should be such that the pencil is exactly at its end.
[Illustration: _Fig. 33._]
=43.= =To draw a spiral curve.= Draw four lines forming a small square
(fig. 33). The point _o_ is taken as the center of the first arc, _i
j_; _s_ is the center of _j k_; _u_ of _k l_; _i_ of _l n_. Then,
to continue the curve, _o_ is again taken as the center for _n p_,
and so on. This method produces a volute in which the coils are at a
considerable distance apart, such as has no special applicability to
horology.
[Illustration: _Fig. 34._]
As the balance-spring of a watch is partially concealed by other
pieces, it is generally sufficient to represent the parts that show
themselves by concentric circular arcs, or arcs described from two
centers. If a more accurate representation be required, the following
method may be resorted to: when working on a small scale it involves
the use of the eyeglass, for the figure (fig. 34,) here given is
exaggerated in order to avoid confusion in the lines, numbers, letters,
etc.
A small circle having been described, it is divided into an even
number of equal parts, say four; a less number than this should never
be adopted. From the same center describe another circle as small as
possible, which will be cut by the two diameters drawn between opposite
points of division numbered 1, 2, 3, 4.
Assuming _a_ to represent the starting-point of the curve, from the
center 1 with radius 1 _a_ draw the arc _a b_; from 2 with radius 2 _b_
draw the arc _b c_; from 3 with 3 _c_ draw _c d_; from 4 with 4 _d_
draw _d s_; then recommencing with 1 and the radius 1 _s_ draw _s f_,
and so on.
The less the radius of the small circle and the greater its number of
divisions, the closer will the successive coils be together. To secure
accuracy when working on a small scale, it is advisable that the center
and the several points be in a thin brass or horn plate, which is
maintained in position by steady pins.
THE MICROMETRICAL DIVIDING TABLE.
=44.= This instrument is no more than a simple application of the screw
to dividing straight lines, but it will suffice to enable the reader to
understand the principles on which the more complicated instruments are
based.
[Illustration: _Fig. 35._]
A plate, P, fig. 35, supports a bracket _a_, in which a screw, similar
to the one described in paragraph =30=, is engaged by means of a
collet; it rotates, being supported between this bracket and the small
bearing _b_, that receives the pivot at the end of the screw.
The screw is fitted carefully into a nut _n_, which is rigidly attached
to the small plate _h_; this carries a fine marker, movable on an axis,
and terminating with a chisel edge or a fine diamond point, according
as the instrument is to be used for engraving metal or glass; or it
may be provided with a fine pencil if the object is merely to make
subdivisions on a drawing.
This being understood, it will be evident that, if a rule or rod of
any form be fixed by screws or otherwise between _f_ and _g_, it can
be graduated by means of the marker, the screw being made to advance;
the millimeter screw can be used for dividing into millimeters and
fractions direct, or, with a little calculation, into fractions of an
inch. Each complete rotation of the head means a displacement of the
marker by a millimeter; a half turn will be half a millimeter, etc.
OTHER METHODS OF DIVIDING INTO EQUAL PARTS.
[Illustration: _Fig. 36._]
=45.= =First method.= Having fixed a sheet of drawing paper on a smooth
board, draw the line M N, fig. 36, longer than the rule which is
required to be divided. Then, with a compass or graduated scale, mark
off a series of equidistant points, commencing at N, equal in number
to the required series on the rule, and let M be the last division.
With the center N and radius N M describe the circular arc _p v_, and
with M as a center and the same radius, describe a second arc _r s_,
intersecting the first at O. Join O with M and N. Assume _a c_ to be
the rule that is to be divided into equal parts; slide it on the paper
parallel to M N until the extremities, _a_ and _c_, coincide with the
lines O M, O N, and are equidistant from O. This position can be easily
found by the aid of a compass with one of its centers at O. Now fix
the rule in position with sealing-wax, or by some other means, and,
with a firm upright pin, center the brass rule R at O, so that it can
rotate round this center on the pin as a pivot. It now only remains to
trace a series of lines O _k_, O _b_, O _d_, etc., with the rule, to
the division points of the line M N. The line _a c_ is thus divided
into as many equal parts as the line M N. The graduations will be all
the more exact according as the divisions of the line M N are longer.
=46.= =Second method.= By the side of the chuck of a wheel-cutting
engine, arrange a horizontal slide _y f_ fig. 37, that can travel
easily in a direction perpendicular to _a_ T. A watch fusee-chain, or
a very flexible spring, is fixed by one end to the chuck, and by the
other to the slide at _d_. The chain or spring is kept stretched by a
weight which tends to draw the slide from _f_ towards _d_.
[Illustration: _Fig. 37._]
The rule to be graduated, _a_, is now fixed on the slide, and an
initial division is marked on it with a pointed rotating cutter in the
position usually occupied by the wheel cutter, or else by striking a
small pointed or flat-edged chisel arranged for the purpose, in such a
manner as not to be liable to derangement.
Rotate the table through a definite distance; the rule _a_ will advance
through the same distance; mark the second division; then having moved
the division-plate through a distance equal to its first displacement,
mark the third graduation, and so on. Suppose, for example, that it be
required to make 30 divisions on the rule between _f_ and _d_; select
on the plate the circle corresponding to twice or thrice this amount,
so that the radius of the chuck may not be relatively too short, and
that the chain or spring may not act at a disadvantage; take the number
60 for example:
The two marks at _d_ and _g_ on the spring indicate the length that
corresponds to the straight line to be divided.
The chuck is placed in the lathe and reduced in diameter until the half
circumference is exactly equal to the distance between these two marks
on the spring, which thus fall on a diameter, _i g_, of the chuck.
The spring having been fixed by its two extremities, the slide with the
rule attached is placed in position, so that the mark _g_ is on the
line _a_ T; it will be evident from the figure that each displacement
of the division-plate through one-sixtieth of its circumference will
cause _a_ to advance through one-thirtieth of the space between _f_ and
_d_.
_Remarks._—Knowing the relation of a diameter to the circumference (as
1 : 3.1416), we can determine the diameter of the chuck at once by
calculation.
Its form should be a true cylinder, and it is well to place guides that
will prevent the spring or chain from assuming a helical position.
The side that carries the rule should be strictly perpendicular to _a_
T; and the portion of the spring that is not coiled on the chuck should
always be parallel to this slide.
The chuck and spring must be quite clean and smooth, and the latter
should be very pliable. A greater weight will be needed to keep
the spring stretched than will suffice for a chain, and it must be
increased as the strength of springs is greater.
The slide, _y f_, may simply travel over a horizontal surface between
pins planted in two parallel lines. But it would be preferable to adopt
some other method, for instance, to make this piece (F, fig. 37),
travel with a little friction along a perfectly true cylindrical rod.
=47.= =Third method.= This is merely an application of the arrangement
mentioned in paragraph =44=. The lathe can be employed for marking
off a series of equidistant points in a straight line. Knowing the
pitch of the slide-rest screw, determine the distance apart in, say,
millimetres, of the required divisions, and fix the rule perfectly flat
on the face-plate, which must be rendered immovable by any convenient
means. Then mark the first point with the drill-stock. Advance the
screw by the amount previously determined upon and mark the second
point. After withdrawing the drill, again advance by the same amount
and mark the third point, etc. Always be careful, before making the
first mark, that the screw has already traveled some distance in the
direction it will continue to move, so as to avoid backlash, or loss of
time.
TO SUBDIVIDE A CIRCLE.
=48.= =To divide the circumference into equal parts.= After having
drawn the circle, A, fig. 38, draw two diameters, _d a_, _b c_, at
right angles to each other, dividing the circle into four equal parts.
Join the points, _c a_, and divide the line, _c a_, accurately into
nine equal parts.
Draw a series of circles concentric with the first, at distances apart
equal to one of the divisions of _c a_, and to the number of one, two,
three, etc., according as it is required to subdivide the circle, say
for a pinion, into seven, eight, nine, etc., equal parts.
[Illustration: _Fig. 38._]
With a fine-pointed compass, measure off the radius of the initial
circle A. Placing one point of the compass at _c_, the other point
will give the position of the next leaf, and so on, all around the
circumference. If the innermost circle A be selected for sub-division,
six divisions will be obtained, and there will be one more division for
each larger circle.
The operation will be facilitated by selecting the first circle, so
that the line _a c_ contains exactly nine divisions equal to those of
some scale that is accessible. Such a circle can be easily found, by
first drawing the two diameters, laying the scale in the direction _c
a_, and determining by trial the radius for which the first and ninth
divisions correspond to _a_ and _c_ respectively.
=49.= =To divide a surface into rings of equal or proportional
superficial area.= The following solution is due to M. Brocot:
Let _a d_ be the radius of a circle (fig 39), that is required to
be subdivided into four rings of equal area by concentric circles.
Taking _a d_ as a diameter, draw the semicircumference, _a b d_;
accurately divide _a d_ into four equal parts, and at each point so
obtained, erect a perpendicular. Through the intersections of these
perpendiculars with the semicircle, draw a series of concentric
circles; they will trace out rings, 1, 2, 3, 4, that have equal
superficial areas.
If it be required to divide the surface in a given proportion, divide
the line _a d_, according to that proportion.
[Illustration: _Fig. 39._]
The right-hand side of fig. 39 gives a special application of this
method to the division into two equal areas of the interior of a barrel
exclusive of the space occupied by the arbor-nut. If the mainspring
accurately covers _i c_ when wound up, and _i j_ when unwound, it will
give the greatest possible number of turns.
TIME.
=50.= Solar time is taken from the revolutions of the earth, and the
watchmaker can easily get the exact solar time of any point at which
he may happen to be by a little calculation from known standards.
These standards are: 1. The zenith. 2. The longitude of the point of
observation. 3. The difference between noon at the point of observation
and noon of a known meridian either east or west of the point of
observation. The zenith is that point in the heavens where the rays
of the sun are in a plane exactly perpendicular to the surface of the
earth at the point of observation, and when the rays of sunlight are
in this plane it is noon at that point. The circumference of the earth
is divided into 360 degrees or meridians of longitude, so that as the
earth revolves once every twenty-four hours, each of these meridians
will pass the zenith, or fixed point, in that time. In twenty-four
hours there are 24 × 60 = 1,440 minutes, so that the interval between
the passage of one meridian and the next will be 1,440 ÷ 360 = 4
minutes. A degree of longitude is divided like an hour, into minutes
and seconds, so that
1 degree of longitude equals 4 minutes of time.
1 minute ” ” ” 4 seconds ” ”
1 second ” ” ” ¹⁄₁₅ or .066 seconds of time.
=51.= Thus it happens that, at a town one degree east of a given
point the sun will be visible four minutes sooner, and if to the
west, four minutes later than at that point. The “local,” or solar
time, therefore, will be four minutes earlier at the first town, and
four minutes later at the second town, than it is at the point of
observation.
=52.= It will be readily seen that, having any two of the three factors
given above, the other can be readily found. Thus having the time of
a given meridian and the local noon or meridian time, the longitude
can be readily found; or, having the longitude (which can be readily
obtained from a surveyor) and the time of a given meridian, “noon,”
can be calculated, etc. The first method is followed in calculating
distances at sea; the chronometer keeping Greenwich time, and the local
noon giving the longitude.
When great accuracy is necessary, however, a fixed star is used as a
means of observing the exact time when a revolution of the earth is
completed, as the revolution of the sun in its orbit causes a slight
variation during the year. For further information on this point the
reader is referred to works on astronomy.
To obviate the constantly varying time in running east or west, the
railroads use the time of a given meridian over each fifteen degrees
of longitude, and as each degree of longitude equals four minutes of
time, it follows that only the hour is changed in changing from one
standard to another. In Europe the zero of longitude, or the time of
the meridian of Greenwich is used. In the United States the time of
the 75th degree, which passes through Philadelphia, is used from the
67th to the 80th degree, which comprises the territory from Princeton,
Maine, to a line drawn north and south, passing through Erie and
Pittsburg, Pa., and is called Eastern time. The time of the 90th
meridian is used from the 80th to the 102d meridian, and is called
Central time. The time of the 105th meridian is used from the 102d to
the 114th meridian, and is called Mountain time. The time of the 120th
meridian is used from the 114th meridian to the coast (which ends at
about the 124th meridian) and is called Pacific time. The time of the
various standards is telegraphed through their various territories at
noon each day, and furnishes an accurate standard of comparison to all
watchmakers.
=53.= In very many cities the actual or solar noon has been discarded
and the railway standard adopted, thus making but one standard and
removing the source of confusion and annoyance to many people. In
others, however, the two standards are still used, and it becomes
necessary for the watchmaker to be able to calculate both standards,
in case of accident or irregularity in his regulator. Hence he should
calculate his longitude within one second by means of the difference
between railroad and local noon, and have the nearest surveyor correct
his reckoning; then, by means of the accurate longitude and the
railroad time, correct the solar time; then by means of the solar
noon and the longitude calculate the railroad time. When all these
calculations check each other perfectly, he possesses all the time data
he needs for that place, and can correct his standard or regulator
if at any time it should become irregular. The calculations are very
simple, and can be easily performed from the data given above.
FOOTNOTES:
[1] Loomis’ Treatise on Arithmetic.
Loomis’ Treatise on Algebra.
Loomis’ Elements of Geometry.
Robinson’s Algebra and Geometry.
[2] Adapted from Robinson’s Algebra.
[3] Determined in the manner explained for erecting a perpendicular in
par. 32 except that intersecting arcs are described on both sides of
the line (_n m_, fig. 17); the perpendicular will be a line joining
these points of intersection.
PART II.
MATERIALS EMPLOYED IN HOROLOGY.
IRON.
=54.= Iron is an elementary body, that is to say it cannot be
decomposed. It is the most tenacious of the metals, having a breaking
strain of about 75 kilo. per sq. mm. (or 106,000 pounds per sq. inch)
of section. Two pieces can be perfectly welded together when raised to
a white heat.
In the smaller horological appliances, the metal is not employed except
after conversion into steel. In common clocks it is used from motives
of economy, for forming pins, screws, etc. In turret clocks, however,
considerable use is made of it, many of the parts after they are formed
being cemented, that is to say, having their surface rendered hard in a
manner subsequently indicated (=65=).
Such a mode of manufacture is particularly applicable to pieces that
are subject to a constant succession of impacts; their hardened,
steelified surface resists wear, while the iron core affords security
against rupture.
It is important to carefully distinguish the cases in which iron is
preferable from those in which its substitution for steel serves merely
to augment the profits of the manufacturer.
The fracture of a good piece of iron is characterized by long twisted
fibres of a brilliant white color.
If heated frequently or carelessly, the quality of the metal is
impaired—it ceases to be fibrous and looses its tenacity: in this
condition it is said to be _burnt_.
It is better to work with a charcoal or gas fire, as coal acts
more rapidly in rendering the metal brittle. Cold hammering, or
“hammer-hardening,” also makes it brittle and diminishes its tenacity,
but this is again restored by a suitable annealing.
Iron dissolves slowly in dilute nitric acid; if not diluted, this acid
rapidly oxidizes it. Dilute sulphuric acid dissolves the metal easily,
but if concentrated, it has no action in the cold, whereas, on heating
to ebullition, the iron is dissolved with evolution of sulphurous acid
gas. It is also dissolved by hydrochloric acid, or aqua regia.
Iron is less magnetic than steel, especially hardened steel, which,
owing to its great coercive force, is magnetized with greater
difficulty, but retains its magnetism for a longer period. Indeed,
_soft iron_, if properly prepared, can be magnetized and demagnetized
instantaneously.
Some workmen can distinguish iron from steel by the musical note
emitted on striking. A more certain method, however, consists in using
dilute nitric, or sulphuric acid. If the surface remains unaltered, or
nearly so, when touched with a drop of either acid, the metal is iron,
but, in the case of steel, a black mark will be left, owing to the
liberation of carbon.
=55.= =To Remove Rust.= The usual mode is to rub the object with a
piece of oiled rag, or emery paper. It appears that more rapid and more
satisfactory results are secured by using very pure petroleum, and
wiping with a hempen or woolen rag.
=56.= =To Prevent Rust.= Dip iron or steel articles in a mixture of
equal parts of carbolic acid and olive oil, rubbing the surface with
a rag. Others rub the metal with a mercurial ointment, leaving a thin
layer over the entire surface. It is stated that, if iron be dipped
in a solution of carbonate of potash or soda in water, the surface
will be protected against rust for a long time, and objects can be
protected for any period by burying in quicklime. Rubbing the surface
with plumbago has a similar effect, and Barff has pointed out that, by
exposing iron to the action of steam, heated above the boiling point of
water, a coating of magnetic oxide of iron is formed, which is equally
serviceable.
=57.= =To restore iron and steel that has been burnt, or badly forged.=
When iron is burnt, or carelessly forged, it becomes crystalline and
brittle; in order to restore it to its original condition, a fresh and
very careful forging is generally needed. This can be avoided by having
recourse to the following method, suggested by Caron: it consists in
treating the metal somewhat after the manner adopted in hardening steel.
He experimented with a bar of good iron, which was easily bent when
cold, without breaking or showing any cracks. It was then burnt and
became brittle when cold, the fractured surface showing brilliant
shining facets.
Prepare a boiling saturated solution of sea-salt, heat the piece of
iron to a bright redness, and plunge it into the bath until it is of
the same temperature (about 110° C. or 230° F.) After undergoing this
operation, it is found that the metal can be easily doubled in the
cold, exactly as it did before being burnt.
Perret states that steel which has been deteriorated by frequent
hardening can be restored as follows: Heat it short of dull redness and
quench in melted tallow, repeating the operation, if necessary, when
the steel may be again hardened in the ordinary manner, and will be
nearly, if not quite, restored to its original condition.
CAST IRON.
=58.= This is only used in the manufacture of tools and large clocks;
the employment of cast iron wheels in the striking train of such clocks
has materially reduced their price.
Like steel, it is a compound body, consisting mainly of iron and
carbon. Cast iron, however, differs from steel in the quantity of
carbon present, for, whereas its proportion in cast iron varies from 2
per cent. upwards, there is never, in steel, an amount exceeding 1.5
per cent., and even .5 per cent. renders an iron hard, converting it
into “mild” steel.
Cheapness is not the only argument in favor of the use of cast iron. In
virtue of its molecular structure, this material offers a considerable
resistance to a crushing strain, so that the teeth of wheels, made
of carefully selected cast iron, will work for a long time without
sensible wear; moreover, the founder’s art has made such important
advances that there is no difficulty in casting, to a constant pattern,
a wheel, together with the pinion that it carries, and any other
projections, etc., that may be required; this economizes labor to a
very great extent.
The use of cast iron in the construction of certain classes of wheels,
and parts of tools, presents advantages which we cannot afford to
ignore; but it must be carefully observed that this material is not
suitable in cases where great accuracy in the acting parts is required,
as it cannot, like brass and steel, be conveniently worked by the
turning tool or file. In recent years, however, this difficulty
has been overcome by the introduction of what are termed “malleable
castings,” produced as follows:
=59.= =Malleable Castings.= The object is first made of ordinary cast
iron, and the invention consists in rendering this malleable by the
removal of the carbon that has served the very important purpose of
rendering the metal fusible. In large cast iron pots, the castings are
laid with alternating layers of powdered red hæmatite, and the whole is
kept at a temperature of about 900° C. (1,650° F.), or cherry-red heat,
for 72 hours. On cooling, the castings are found to consist of nearly
pure iron, and to be perfectly malleable, and, therefore, workable.
STEEL.
=60.= The treatment of steel involves some of the most prolonged and
delicate operations in the entire range of horology. If the metal is
badly selected and prepared, the working of it will be laborious,
difficult and unsatisfactory; the resulting object will be distorted
in the hardening, and will not harden uniformly; in short, it will
occasion much toil and loss of time, with very little success.
Let the young watchmaker accustom himself from the first to study the
steel that he uses, so that he may be thoroughly cognizant of both its
advantages and defects; he will, in the practice of his art, be amply
repaid for the brief time spent in making such an examination.
=61.= Steel is not an elementary body; it is usually regarded as a
carbide of iron, that is to say a combination of carbon and iron.
Analysis, however, proves other substances to be usually present in
almost infinitesimal quantities; their remarkable influence on the
physical properties of the metal has not yet been fully investigated,
but much attention is being devoted to them at the present day.
The varieties of steel are very great. What are known as _puddled_
and _natural_ steel are obtained by acting directly on cast iron.
_Cementation_ is a very old method of converting bars of malleable or
pure iron into steel by enclosing them in charcoal and heating the
whole for several days, until the carbon has worked itself into the
center of the bars in such quantity as to covert the iron into steel.
The steel obtained by the above method is very heterogeneous; in other
words, the composition is not uniform throughout a given block or
bar. One part is highly carbonized, whereas another part, especially
towards the center, will not be sufficiently so. The _grain_, although
very fine in one part, will be more coarse in another; hard particles
of pure cast iron, termed “pins,” are to be met with that resist
the action of the graver or the file and give rise to cracks in the
hardening, hammering, etc., and portions or sometimes even entire
layers that have taken up no carbon whatever. The differences in the
density, hardness, malleability, etc., that can be shown to exist at
different points in the same bar arise from this cause.
Such faults can in part be corrected by _shearing_, an operation which
consists in binding together a number of bars in a bundle, raising
them to a red heat and beating them with sledge or steam hammers so as
to weld them into one. The bar thus obtained is again heated, folded
several times on itself, again hammered, rolled, etc., when it is
termed _shear steel_. If these operations are performed carefully and
without a too great heat, the quality of the steel is much improved;
it is more homogeneous and can be worked with greater facility.
=62.= The discovery of the earliest method of producing _cast_ steel,
thoroughly homogeneous, was made by a watchmaker, B. Huntsman, of York,
and metal produced by his method is very highly prized at the present
day. Many other methods have been since introduced, amongst which may
be mention the Bessemer and the Siemens-Martin processes, and steel
is now produced from iron of very varying quality, so that the mark
_cast steel_ is now far from being a guarantee of quality. The fusion
of shear or cement steel will only secure a marked superiority in its
quality under two principal conditions: (1) The metal must be carefully
selected, since certain qualities do not intermingle thoroughly. (2)
Very great care and skill must be devoted to all the operations, the
successive heatings, forging, rolling, etc.
In short, in the case of steel it is exceptionally true that we must
never accept the metal merely on its own recommendation. Whatever
maker’s mark is selected, the results obtained will never be
satisfactory unless the degree of hardness, the elasticity, cohesive
force, etc., are such as will suit the metal to the special purpose to
which it is to be applied as well as to the working it will have to
undergo. _Experiment can alone make us fully cognizant of the qualities
of a steel._
GENERAL OBSERVATIONS.
=63.= All steels, if of good quality to begin with, will deteriorate
if subjected too often or too long (according to the character of the
metal) to the action of either the fire or the hammer. They will become
brittle and incapable of hardening, in the end even reverting to the
condition of iron.
The quality of steel becomes worse as the number of flaws, blackish
filaments, more or less carbonaceous veins, and occasional particles of
pure iron in its substance are greater; as its surface is _cindery_,
that is to say spotted with minute black marks which become more
prominent after polishing, etc.; as its fracture presents an uneven
grain, etc.
Such a metal is found to vary considerably as regards hardness,
elasticity, etc.; not being uniformly affected in the hardening, it
becomes difficult to work with the file and almost impossible to form
into a perfect cylinder in the lathe.
Other conditions being equal, these faults are characteristic of
natural steel rather than of the two other varieties. At the same time,
if well sheared, it becomes very elastic, and has the great advantages
of not being deteriorated under the hammer and of being less ready than
the other varieties to be converted into iron.
Rolling, wire-drawing and hammering occasion a molecular
re-arrangement; it is necessary, therefore, to anneal the metal from
time to time, as otherwise it becomes brittle or cracks.
There is a certain temperature, corresponding to each variety of steel,
which cannot be exceeded without the metal being injuriously affected;
this temperature must, then, be previously determined.
The grain of a piece of steel that has been superheated or _burnt_
is characterized by brilliant diamond-like particles; the mass loses
its beautiful color, and resembles iron more or less according to the
degree of heat applied.
Some few workmen are enabled, by long experience and a very delicate
touch, to judge approximately of the quality of a steel from its
weight, feel, and resonance. Metal that is of a good quality,
homogeneous, and very dense, they term _full_.
SPECIAL OBSERVATIONS.
=64.= =Natural Steel.= In the case of natural steels of low quality,
the fracture is usually characterized by uneven grains, a somewhat
fibrous nature and a bluish tint. The grain becomes finer and more
even and the surface presents more and more the appearance of a
piece of coke, as the quality of metal improves. In addition to
these distinctive features a natural steel of high quality can be
distinguished by the fact of its being more thoroughly hardened and
less liable to break when hard.
In hardening it must be raised to a higher temperature than cement
steel; in other words, steel of a low quality must be heated somewhat
above bright redness, while the better qualities should be heated to an
orange-red, or nearly so (=77=).
=65.= =Cement Steel.= The cement steel ordinarily met with has a
lamellar fracture, the lamellæ varying in form and color from the
center towards the circumference. The grain is usually finer and more
uniform than that of natural steel, there is seldom any appearance of
fibres, veins, or flaws. The color of the fracture is greyish, tending
towards blue in the ordinary qualities.
The better qualities are marked by a closer grain, a more uniform,
dull, greyish-white color, exhibiting neither streaks or black spots
after hardening, and by the further fact that hardening can be effected
at a lower temperature. If of the very best quality, it should not
require heating beyond a clear cherry-red; often even a still less
degree of heat will suffice.
=66.= =Cast Steel.= Cast steel is the most homogeneous, full, and
beautiful of the three classes. Several varieties exist. The fracture
of cast steel, as compared with others, is smooth, compact, and of
a white-grey color, resembling coke. The grain is fine and very
even. The metal must be hardened at a temperature much lower than
can be safely applied to other classes of steel, since it is rapidly
deteriorated by heat.
Cast steel is more fusible than ordinary steel, and will fracture with
ease under the hammer when heated to a blue tint, so that great care is
essential in hammering it.
The metal should never be heated beyond a dull or cherry-red heat, lest
it be _burnt_.
The tenacity will be increased by forging at a low temperature or even
by cold hammering.
The fineness in grain, together with its high density, afford an
indication that the metal can be rendered very uniformly hard; that
very fine cutting edges and the most minute rods can be made of it;
and that, after hardening, it can be highly and uniformly polished;
in other words, that it does not exhibit spots or streaks differing
in color from the mass, as is always the case with natural and cement
steels. For most horological purposes (such as making pinions, staffs,
pivots, etc.) cast steel is preferable. It is the only kind that can
with certainty be highly polished, turned perfectly round, and that
does not get distorted in the smoothing. Moreover, when wear does occur
it exhibits less irregularity.
Highly-carbonized shear steel exhibits a fine, close grain that would
make it easily mistaken for cast steel. They can be best distinguished
by the application of dilute sulphuric acid. The side of the bar when
acted on by this means exhibits lines that indicate the junctions of
the several layers constituting shear steel.
DETERMINATION OF THE QUALITIES OF STEEL.
=67.= It is unnecessary to observe that as we are writing mainly for
the use of practical watch and clockmakers, we shall make no reference
to those elaborate systems of testing that form a remarkable feature
of the engineering of the present day, but shall confine ourselves to
the tests which workmen can apply for themselves.
When the grain is fine, close and homogeneous, the fracture in even
curved lines and the surface of a uniform grey aspect, the metal is
considered to be of good quality. It is, nevertheless, unsafe to rely
too much on such indications, for a steel that has been hammered
until cold will exhibit a fine close grain, whereas the grain of the
same metal will be coarse and open if it was still red hot when the
hammering or rolling was concluded. The grain of hardened steel,
moreover, depends on the degree of heat to which it has been subjected.
When of equal quality, even if from the same maker, the grain will be
finer in bars of small dimensions than in those that are larger.
Cast steel even, especially in large pieces, is not always perfectly
homogeneous, as can be easily perceived on applying the file, or
still better, in the lathe; an object can with difficulty be turned
perfectly round, and loses its shape in the smoothing. _As a general
rule it is impossible to form a reliable opinion on a specimen of steel
until after it has been worked, filed, turned, and tested according
to the particular use to which it is to be applied; for a steel that
is excellent for making, say, a spring or a cutter, may be quite
unsuitable and give most unsatisfactory results if used for making
staffs or fine pivots, or the converse may be equally true._
As a preliminary test, break a piece of the metal; after having
examined the fracture, form a cutting edge, harden to what seems to be
a convenient degree, then sharpen and employ for cutting small pieces
of iron. If the edge is in no way damaged by the iron, this may be
taken as a good indication that the metal possesses body and tenacity,
and that it can be hardened as much as is required for such purposes.
The following are methods of obtaining more complete information as to
the homogeneity, the character of grain, the degree of hardness a given
sample can attain, as well as its malleability, body, elasticity, etc.
=68.= =Homogeneity.= Place drops of dilute sulphuric acid equidistant
along the surface of a bar. If the metal is homogeneous all the drops
will impart the same color.
Cold hammer or hammer-harden, and then fire-harden part of the bar.
Break off the extremity in order to study the fracture; if the result
of this examination is satisfactory, polish the hardened end carefully,
and with the aid of a glass again examine into the homogeneity of the
metal. The polish will be the better and more uniform according as the
steel is more homogeneous.
=69.= =Grain, hardness and temperature of hardening.= All varieties
of steel do not harden to the same degree, and each requires to be
heated to its own particular temperature for hardening; moreover, the
character of the metal, its color, and the size of its grains vary
according to the degree of heat to which it is subjected. It would be
difficult to draw any exact conclusions as to the character of grain
and the hardness without the following practical method, which we owe
to Reaumur:
At a temperature not exceeding a dull redness, forge a piece of the
steel to be tested into the form of a razor-blade, that is to say,
leaving it thick on one edge and thin on the other, in the direction of
its length. Then heat the blade, holding it by one end, and when the
other end has reached a bright red heat, plunge the whole into water.
Part of the steel will then be hard hardened. Along the entire length
of the thinner edge carefully break off the metal with a hammer or
otherwise, and examine the character of grain at different points of
the exposed thicker edge thus left.
As the form, color, etc., of the grain depend on the degree of heat to
which each portion was subjected, it follows that we shall observe four
types of grains: (1) Large, white, sparkling grains; (2) Grains that
are medium sized and intermixed, some being white and sparkling, others
white and dull; (3) Fine dull grains; and (4) Grains that are medium
sized, but dull and ill-defined.
According as the third class of grains is observed to be more numerous
than the second class, so is the fineness of the steel greater, and
conversely.
This method of testing possesses, moreover, the advantage that the
workman can experiment on his blade of steel with a view to determine
the temperature best suited for hardening.
Grain No. 1 corresponds to a white-red heat for hardening.
Grain No. 2 corresponds to an orange-red heat for hardening.
Grain No. 3 corresponds to some shade of cherry-red heat for hardening.
Grain No. 4 corresponds to a dull red heat for hardening.
As there is some difficulty in remembering the exact points at which
these several temperatures are reached we will complete this account of
the mode of testing by the following:
=70.= On a thick plate of metal, maintained at an orange-red heat,
place three fragments of the steel under examination, previously
marking them, so as to observe the order in which they are immersed
in water; and have three vessels of water standing near. As soon as
one of the pieces reaches a dull cherry-red heat, allow it to slide
into one of the vessels; heat the second to a medium cherry, and the
third to a bright cherry-red, introducing them in succession into
the water-vessels. If these pieces be examined as to the resistance
they offer to breaking, and the fracture of each be compared with the
fracture at different points of the razor-blade, the file being used
to test hardness, we shall have sufficient evidence as to the most
suitable temperature for the hardening of this particular variety of
steel.
=71.= =Body.= A steel that possesses _body_ is not brittle. This
quality may be tested in the following manner: Several bars of
different kinds of steel, of equal dimensions and hardened as uniformly
as possible, are bent until the breaking point is reached. If all
the conditions of the trial are identical, those bars that stand the
greatest angular deflection without breaking have the most body.
Steel that possesses body does not break as easily as that which
is wanting in body. Its fracture will be, as it were, bevelled off
like the mouth-piece of a whistle. If soft and fibrous, it will be
characterized by parts being torn asunder.
=72.= =Elasticity.= The elasticity may be tested in a similar manner.
It is proportional to the curvature or to the weight that a rod or
blade of the metal under examination can support without failing to
return to its initial position as soon as the weight or obstacle is
removed. A sample of steel that is distorted by a weight that another
specimen resists, is evidently inferior in elasticity.
=73.= =Malleability, tenacity, ductility.= A cold hammering, if
carefully managed, will suffice to indicate the limits between which
steel will support frequently repeated percussion, without breaking,
cracking or flying.
Forge a piece, introducing it a number of times into the fire in order
to ascertain whether it loses its distinctive characteristics rapidly,
and whether it can be successfully forged.
It is more difficult to forge, according as it is harder and more
“steely.”
The degree of malleability is indicated by the manner in which it
supports hammering and rolling, and by the smallness of the dimensions
to which it can be brought by such operations.
Passing the metal through a draw-plate with smooth holes, or tapping it
in a screw-plate will give useful indications as to degree of ductility
and tenacity.
A metal is said to be _malleable_ when it can be easily spread out
under the hammer or in the laminating rolls. It is called _ductile_
when it can be reduced to very thin wire by passing through the
draw-plate.
It would seem that these two properties, ductility and malleability,
should always exist together, to the same degree, in any given metal,
but such is not the case. Iron can be drawn into very fine wire, but
cannot be reduced to sheets of relatively equal thinness; tin and lead
give leaves of extreme thinness, but cannot be drawn out into very fine
wires; gold and silver are both very malleable and ductile, and they
rank highest as regards the possession of these properties.
Steel is more fusible and malleable than iron, but less ductile.
=74.= _Observations._ Formerly the makers of cylinder escapements
preferred forged steel, and their cylinders often cracked after the
hardening: modern makers employ drawn steel, and it is much preferable.
At the same time they do not appear to recognize the principal reason
for the difference in the two varieties of steel. It seems to us to be
as follows: forged steel is malleable; drawn steel, which has passed
well through the draw-plate, is ductile, and, therefore, tenacious. But
tenacity in a metal is nothing else than an exceptional resistance,
opposed by its particles to a fracture or separation; it follows, then
that drawn steel will crack with less facility than the other.
PREPARATIONS OF STEEL.
=75.= When a variety of steel has been selected that possesses the
requisite properties: that is to say, fibre and elasticity for springs;
body and tenacity for circular cutters, gravers, etc., it must be
prepared; in other words, it must be made so that it can be worked with
ease, for steel that is badly prepared will resist both the file, the
graver and the drill. It can never be turned perfectly round, and will
harden unevenly.
=76.= =To anneal steel.= The commonest, and at the same time best,
method consists in heating the metal to a dull, red heat, burying it in
hot ashes and allowing it to cool slowly.
Steel raised to a red heat in contact with air loses a portion of its
carbon, so that it is better to place the metal in a vessel of burnt
clay; this is introduced into a fire which must not be too bright at
first, and when the vessel has attained a red heat the fire is checked
and left until the whole is quite cold.
In order to soften steel by annealing with a view to work it, engineers
entirely cover the metal with dry powdered wood charcoal or dry iron
filings or turnings, in a cast iron box or pot, or in a crucible,
shutting up all the openings so as to protect it from the direct
action of the fire and from the air. The vessel is then put in a dull
fire, the heat being gradually raised until the whole has acquired
the requisite temperature, which is known by observing the color (see
the following table); this degree of heat is maintained for about
ten minutes and the fire quenched, after which it must be allowed to
gradually die out. Frequently the cooling is not complete for a day or
two, and even more when the crucible is of large dimensions.
The metal will become softer, according as the cooling is more slowly
effected. It is generally heated to 800° or 900° C. (1500° or 1600°
F.), a cherry-red heat. When the steel is associated with brass, as in
the case of a compensation balance, it is not safe to exceed 600° C.
(1000° F.)
=77.= It will be useful here to give the following table, compiled by
Pouillet, of the temperature, as indicated by the air-thermometer,
corresponding to various colors of a heated body:
Incipient red heat corresponds to 525° C. ( 980° F.)
Dull red ” ” ” 700° C. (1280° F.)
Incipient cherry-red ” ” 800° C. (1470° F.)
Cherry-red ” ” 900° C. (1650° F.)
Clear cherry-red ” ” 1000° C. (1830° F.)
Deep orange ” ” 1100° C. (2010° F.)
Clear orange ” ” 1200° C. (2190° F.)
White ” ” 1300° C. (2370° F.)
Bright white ” ” 1400° C. (2550° F.)
Dazzling white ” 1500-1600° C. (2730-2910° F.)
=78.= _Annealing or softening in water._ Instead of allowing a piece
of steel to cool slowly, it may be thrown into water when heated to
a temperature just below that at which it would harden. In this case
the metal will not harden, but, on the contrary, become very soft.
A single operation suffices for certain varieties of steel, but with
others it must be repeated.
The only difficulty consists in fixing upon the precise moment at which
the metal has the requisite tint (a purplish yellow or dull red), and
this is more especially felt when dealing with small pieces; experience
can alone guide the workman in this matter.
A skilful workman recommends the employment of water containing
one-fifth of its weight of gum arabic. He also recommends that the
metal be wiped over with an oiled rag, then held in the fire, and, as
soon as the oil is converted into a thick smoke, and is on the point of
igniting, to immerse in water.
=79.= =Hammering steel.= Watchmakers who are called upon to manipulate
exceedingly small pieces of steel, can somewhat increase the body and
homogeneity of the metal by a cold hammering. After annealing, the
object is hammered with light, uniform blows, again annealed, and the
same operation is repeated one or more times, according to the degree
of malleability already acquired by the metal. Steel thus prepared
has more body; the particles composing it are more closely pressed
together; it files and turns well, can be heated more evenly, and
is not distorted or only very slightly in hardening, providing the
requisite precautions are taken.
=80.= _The hammer and anvil._ It is important that in these operations
the surfaces of the hammer and anvil employed be perfectly smooth and
even polished. If they are rough or cracked, if they are uneven or have
a grained surface, a flaw will be produced in the body of the steel or
a crack on its surface.
=81.= =To clean rough steel.= The black coating known as “scale,” which
covers the surface of the metal after it has been in the fire, will
rapidly spoil gravers and files, and, in addition to this, it leaves
behind in them excessively hard particles that will become imbedded in
the steel itself after a clean surface has been exposed. It is then
essential, in order to ensure good and rapid workmanship, to previously
remove this crust from the surface.
This can be done in two ways: by using a rapidly-revolving grindstone,
which instantaneously removes the oxide, at the same time smoothing the
surface of the steel; or by leaving it for a sufficient length of time
in dilute acid, by which the superficial oxide is dissolved.
Sulphuric acid is usually preferred; in addition to the cleaning, it is
said to produce an effect somewhat similar to annealing. On withdrawal
from the acid, the steel must be thoroughly washed with water and wiped
dry with care.
=82.= =Ordinary mode of preparing steel.= When the metal has been
annealed by one of the methods indicated above, its preparation is
completed by “pickling” in acid, after which it is hammered cold
between an anvil and hammer (=79=, =80=). When the metal has been
worked, it is heated to a bluish tint, and after cooling slowly is
ready for the hardening.
=83.= _M. Covillot’s mode._ This author adopts a method whereby he
obtains steel that is very soft to work and perfectly free from hard
grains or “pins” of cast iron, which are so often to be met with in
steel, causing it to crack in consequence of their inability to spread
under the hammer.
Take some garlic, the younger the better, mix it with sufficient good
walnut-oil to cover the garlic and form into a paste; then place it in
an earthenware pot on the fire. When beginning to boil, heat the steel
to dull redness and plunge it into the boiling paste. Withdraw it with
a quantity of oil and garlic adhering; again heat to redness and plunge
into the paste. This operation may be repeated two or three times. Then
heat the steel, while inclosed in an iron tube or box placed on the
fire, and allow the whole to cool. Finally, the steel may be finished
by setting it to _cook_ (if we may use such an expression) for ten or
twelve hours in the composition of garlic and nut-oil.
The last operation may be performed by setting the boiling solution
over an oil-lamp, after depressing the wick in such a manner that the
paste may be kept just simmering.
M. Covillot employed the same mixture for hardening the objects; but
then, of course, it must be cold.
HARDENING.
=84.= It is well known that by the operation of hardening, which
consists in heating a piece of steel to a red heat and immediately
chilling it, the hardness is very materially increased.
Hardening increases the dimensions of the object. A steel collar
adjusted to fit a cylinder will slide on more easily after hardening.
Rolled steel is more liable to be distorted in the hardening than metal
which has been forged or hammer-hardened. As a general rule, when
steel—especially cast steel—has been carefully annealed, cold-hammered
and, after working, heated to a blue temper and slowly cooled, it will
not be distorted in the hardening, providing the heating is skillfully
conducted, and if, at the moment of introducing the object vertically
into the bath, the heat is evenly distributed throughout. Some
practical men affirm that the mere presence of an oily layer on the
surface of the water will check the tendency to distortion.
A workman frequently pretends that he has some exceptionally good
solution for hardening, of which a great mystery is often made; but it
is very generally admitted by those who are well-informed that these
so-called secrets are a delusion and in no sense superior to pure
water. There is a certain amount of truth on both sides, and the former
class are somewhat justified by experiments with the various solutions
enumerated below. We may, however, lay down the three following
conditions as essential to the successful conduct of the operation of
hardening: (1) _The steel must previously be carefully prepared and
worked_; metal that has been skillfully hammered cold or below a red
heat, for instance, will harden better than when not so treated; but
if hammered too much or carelessly, it will crack; (2) _The method of
heating_ should be such that the heat is evenly distributed throughout
the object; if, on immersion, its temperature is not uniform, the
degree of hardness will vary; (3) _The skill of the workman_ must
enable him to detect the exact degree of heat the variety of steel
can withstand, and this must on no account be exceeded, for in that
case the steel will lose tenacity, will be more or less _burnt_, &c.
In the case of irregular shaped articles, considerable skill is often
needed to ensure that the several parts of the mass shall be cooled at,
approximately, the same rate.
=85.= =Methods of hardening.= The baths used for hardening may be
classed under three heads: _Tough_, _Hard_, and _Glass-hard_. It must
be understood, however, that these classes may be made to merge more or
less into one another, by varying the degree of temper.
=85a.= The following receipts are drawn from
various sources, and the reader is recommended to select the one which
he finds on trial to be best adapted to his requirements, for, as Prof.
Akerman has pointed out, there are very many conditions exceedingly
difficult of calculation that influence hardening, and hence it follows
that a workman accustomed to hardening often considers that only one
method, which he has been in the habit of employing, can be used for a
certain purpose, while another equally skillful workman can only attain
the same result by a method essentially different.
I. _Tough._ Tallow; tepid water; oil; resin; sealing-wax; lead;
beeswax; a solution of 3 to 4 parts (by weight) of gum arabic in 100
parts of water; 1 part of soft soap in 100 parts of water; cold water
with a layer of oil over it, the thickness of which varies with the
degree of hardness required; 10 parts mutton suet, 5 parts resin, 2
parts sal-ammoniac, and 35 parts olive oil.
II. _Hard._ Cold water; water containing various salts, such as
sal-ammoniac and sea-salt; a solution of 5 parts sea-salt and 1 part
sal-ammoniac in 20 parts of water; 4 parts sulphuric acid, 50 parts
sea-salt, 10 parts alcohol, and 1,000 parts water (all by weight); 4
parts sulphuric acid, 1 part nitric acid, 1 part pyroligneous acid in
1,000 parts water (to be used very cold).
III. _Glass-hard._—Mercury; nitric acid; opium; any cyanide.
=86.= As a rule it is well to employ tallow for the hardening of small
objects in which hardness without brittleness is needed. Oil renders
the surface harder than the interior, and soapy water has the same
effect. Saline solutions generally give great hardness. Very minute
drills may be hardened by simply whisking them about in the air after
heating the blade to redness, and small objects may be hardened by
pressing between two cold surfaces, as those of the hammer and anvil.
If hardened in nitric acid, opium, or mercury, the hardness of steel is
so great that it will easily cut glass. But such steel is brittle and
all the more delicate according as the precise temperature necessary
(which is not very high) has been exceeded. For it must always be borne
in mind that steel which has been heated too highly has deteriorated in
quality and will remain brittle.
=87.= =Precautions to be observed in hardening.= In the case of
delicate pieces it is necessary to avoid the use of the blow-pipe, as
the current of air causes the surface to scale, and, as is well known,
the metal being unevenly heated will be distorted in the hardening, and
will not be uniformly hardened.
It is better to enclose the article between two pieces of ignited
charcoal, or in a metal tube, or to bring it in contact with a
sufficiently hot piece of metal, etc. An excellent plan is to heat
the article in a bath of hot lead, or of lead and tin in proportions
dependent on the temperature required. The heating is thus exceedingly
uniform, and, if operating in a dark room, the temperature can be
accurately judged.
When it is required to harden an object without discoloring the surface
or destroying the polish, it may be placed in a tube, and completely
surrounded with powdered wood charcoal, or, preferably, animal
charcoal. The whole after being heated is plunged in water without the
steel being in any way exposed to the air. The powder must be heaped up
as a precaution against access of air. On being taken from the water,
the steel is at once placed in alcohol, and if at all dull it will
generally be only necessary to rub the surface with a little rouge.
It is essential that the animal charcoal be previously heated in order
to expel moisture, as otherwise it would adhere to the surface and
produce marks and even irregularity in the hardness.
As a rule the object must be immersed in the cooling liquid vertically
in the direction of its greatest length, and if of unequal thickness,
the stout portion should touch the surface first, so that the metal
may cool more uniformly. In hardening large masses of steel, various
devices are resorted to in order to insure uniformity in the cooling,
but space prevents us from entering more fully into this interesting
question.
The vessel must be of such a depth that the object will not reach the
bottom until quite cold. It is liable to distortion if introduced
sideways, or if the vessel is too shallow.
The method described above for protecting the surface from the action
of the fire should be adopted when hardening delicate or complicated
articles; but in the case of drills, for instance, a simple coating of
one of the following preparations is sufficient.
When an object is hardened in a saline solution, it is well to cover
it with a paste composed of water, salt and flour (some use yeast and
salt for this purpose), or a thin clay. This precaution prevents any
blistering or oxidation of the surface. If it be desired to avoid
oxidation, and, at the same time, to restore to the steel the carbon
it has lost owing to the action of the fire, it must be rolled, while
still wet, in another paste, containing powdered horn or leather, or
some such calcined animal matter. Delicate parts can also be protected
by a layer of beeswax and olive oil made hot.
In hardening small drills, very good results are obtained by enclosing
the blade in a pellet formed of prussiate of potash, lard and Castile
soap, and cooling in beeswax, or the surface may be protected by a
layer of soft soap.
Steel as forged, that is with the thin scale on, is less liable to
break in hardening than if previously brightened, for the scale causes
it to cook, and, therefore, contract more slowly. At the same time it
should be borne in mind that when the surface is bright the hardness
will be somewhat greater.
It will be well to warn the beginner that, if an object is not entirely
immersed in the cooling liquid, it should never be held still, but
rapidly moved up and down, as otherwise there is a liability to crack
at that part which was level with the surface.
As a watchmaker only uses steels of the best quality, he should, in
hardening never exceed a cherry-red heat, and cherry-red comprises
three distinct tints (=77=); incipient cherry-red, cherry-red, and
clear cherry-red. The second of these should not be exceeded in
hardening cast steel, and the third should be taken as an extreme limit
in the case of shear steel.
Ice-cold water should never be employed, but the extreme chill should
be first taken off. Indeed, it is found that frosty weather interferes
materially with the operation of hardening.
Some workmen maintain that the hardening is done better if the water
has been long used for the purpose without renewal.
TEMPERING.
=88.= Hardened steel is extremely fragile, but its tenacity may be
restored by _tempering_, that is to say, by heating it to a degree
dependent on the amount by which its original softness has to be
restored. The color of the metallic surface will gradually change as
the temperature rises, each tint corresponding approximately to the
degree of heat given in the following table (Stodart):
1. Very pale straw yellow 220° C. (430° F.) }
2. A shade darker yellow 235° C. (450° F.) } Tools for metal.
3. Darker straw yellow 245° C. (470° F.) } Tools for wood and
4. Still darker straw yellow 255° C. (490° F.) } screws, taps, etc.
5. Brown yellow 260° C. (500° C. 500° F.) } Hatchets, chipping
6. Yellow, tinged slightly } chisels and other
with purple 270° C. (520° F.) } percussive tools,
7. Light purple 275° C. (530° F.) } saws, etc.
8. Dark purple 290° C. (550° F.) }
9. Dark blue 300° C. (570° F.) } Springs.
10. Paler blue 310° C. (590° F.) }
11. Still paler blue 320° C. (610° F.) } Too soft for the
12. Still paler blue, with tinge } above purposes.
of green 335° C. (630° F.) }
=89.= It will facilitate the precise determination of these points if
it be remembered that
An alloy of 1 part lead and 1 part tin (by weight)
melts at 196° C. (385° F.)
Metallic tin ” ” ” 230° C. (446° F.)
An alloy of 2 parts lead and 1 part tin ” 240° C. (465° F.)
Metallic bismuth ” ” ” 270° C. (520° F.)
An alloy of 5 parts lead and 1 part tin ” 290° c. (550° F.)
Metallic cadmium ” ” ” 310° C. (590° F.)
Metallic lead ” ” ” 320° C. (608° F.)
=90.= Before proceeding to temper an object, at least one of its faces
must be smoothed with pumice-stone, oilstone dust, or emery paper, and
the surface must be left perfectly clean, care being taken to avoid
contact with the fingers, as otherwise it will be difficult to ensure
the requisite tint being obtained.
Tempered to any shade between Nos. 1 and 6 the steel will, if
previously well hardened, be left too hard to be worked by a file or
graver; heated beyond No. 10, it can no longer be much bent without
distortion.
When the quality and the degree of hardness of steel differ, the temper
corresponding to a given tint will also vary. As a rule, hardened cast
steel, tempered to No. 8, will be found as soft as natural steel which
has been let down to No. 9, or even to No. 10.
A piece of steel can be let down to the same tint several times in
succession without altering its properties.
If a good and uniform color is desired, the steel must be highly
polished, as the oxidation of rough parts will render the tint
irregular. The rouge employed must not be too dry, and, if the
burnisher is used, care should be taken that it acts on the entire
surface. Metal of a bad quality, which will not take an even polish,
can rarely be nicely blued.
When the object is finely _smoothed_ with a uniform white surface, very
good results may be obtained; but in such cases the cleaning must be
carefully conducted, as the presence of minute greasy particles will
always render the color irregular, and may even entirely prevent its
appearance.
A uniform color can only be obtained by heating the object in such a
manner that its temperature is raised evenly throughout.
The tempering may be performed by placing an object on the _bluing
tray_, a thin metallic plate, often covered with a thick layer of
fine brass filings, which should be renewed for each operation; or on
a thick piece of metal previously heated to a sufficient degree; on
ignited charcoal covered with a layer of white ash; in a bath of molten
metal, the temperature of which corresponds to the requisite degree of
heat, or the object may be laid on the surface of such a bath, etc.
Some watchmakers when letting down a piece of steel immerse it in water
to check the action; but by so doing they produce an exactly contrary
effect. If a piece of steel be cooled suddenly in water as soon as it
assumes any given color it will be _softer_ than if left to cool in the
open air (=78=).
At one of the blue tints, steel possesses its _maximum elasticity_. The
exact shade varies with the different qualities of steel.
If a hardened and tempered spring has lost its initial elasticity, this
may be restored or even improved upon by gently hammer-hardening, and
after whitening with emery, again tempering to the proper blue tint.
=91.= A very convenient way of tempering a large number of small
articles at a time, heating them with absolute uniformity, is to place
them in a small vessel with sufficient tallow or cold oil to cover
them; the whole is then heated to the requisite degree, which may be
determined by a thermometer or by observing the smoke. When smoke
is first seen to rise, the temper corresponds to No. 2 in the table
(article =88=). Smoke more abundant and darker corresponds to No. 5.
Black smoke still thicker, No. 7. Oil or tallow takes fire with lighted
paper presented to it, No. 9. After this the oil takes fire of itself
and continues to burn. If the whole of the oil is allowed to burn away,
the lowest temper in the table is reached.
It is often convenient to simply smear an article with oil or tallow,
and hold it over a flame or piece of hot iron. The temper can then be
judged in the manner just explained.
With a view to combine the two operations of hardening and tempering,
M. Caron suggested that the temperature of the water used for hardening
be heated to a pre-determined degree. Thus the requisite temper may
be given to gun-lock springs by heating the water in which they are
hardened to 55° C. (130° F.).
TO WHITEN AND BLUE STEEL.
=92.= Some makers of watch-hands and balance-springs, when they are not
satisfied with the color assumed by an object in tempering, immerse it
in an acid bath, which whitens it, after which the bluing operation is
repeated.
We have seen watchmakers whiten small pieces of steel with a piece of
pith moistened with dilute sulphuric acid, but the method cannot be
recommended.
Others fix fine steel work, a watch-hand for example, with wax on a
plate, and whiten it by means of pith and polishing rouge, or a small
stiff brush charged with the same material. It is then detached, by
heating, and cleaned in hot alcohol.
These methods, if judiciously employed, are of great service, but it is
important to remember always to thoroughly wash after the use of acid,
and then to allow the object to remain for a few minutes in alcohol.
Sulphuric acid does not whiten well. It often leaves dark shades on the
surface. Hydrochloric acid gives better results.
=93.= =To blue steel uniformly.= In order to secure a uniform color in
tempering or bluing, it is essential that the smoothing and polishing
should have been very evenly done. The surface must be perfectly clean;
for otherwise parts that are greasy, or on which the rouge has remained
too long, or has been too dry, will not exhibit the same tint as the
rest. The heat must be uniformly distributed. This is why, when bluing
screws in a perforated bluing pan, it is customary to lightly strike
the handle, for the vibration and the perpetual change in the contacts
ensures their receiving the heat more evenly. A similar purpose is
served by placing the pieces in brass filings. Steel must not be
tempered while only in contact with bodies that are bad conductors of
heat, stone, either in powder or block, for example; because, as we
have already observed, the distribution of heat would occur unevenly
throughout the metal.
Watchmakers secure a uniform tint more easily by using an iron or
copper polisher than one of any other metal.
=94.= _To blue small pieces of steel evenly._ If the foregoing
precautions are carefully observed, the following methods will give
satisfactory results:
First blue the object without any special regard to uniformity of
color. If it proves to be imperfect, take a piece of dead wood that
does not crumble too easily, or of clean pith, and whiten the surface
with rouge without letting it be too dry. Small pieces thus prepared,
if cleaned and blued with care, will assume a very uniform tint.
A clever mechanic assures us that he easily obtains a similar result by
rubbing the surface, after it has been well smoothed, with the end of a
stick that has been partly burnt in the fire.
=95.= _To blue a clock hand or a spring._ To blue a piece of steel
that is of some length, a clock hand for example; clockmakers place it
either on ignited charcoal, with a hole in the center for the socket,
and whitened over its surface, as this indicates a degree of heat that
is approximately uniform, or on a curved bluing tray perforated with
holes large enough to admit the socket. The center will become violet
or blue sooner than the rest, and as soon as it assumes the requisite
tint, the hand must be removed, holding it with tweezers by the socket,
or by the aid of a larged-sized arbor passed through it; the lower side
of the hand is then placed on the edge of the charcoal or bluing tray,
and removed by gradually sliding it off towards the point, more or less
slowly according to the progress made with the coloring; with a little
practice, the workman will soon be enabled to secure a uniform blue
throughout the length, and even, if necessary, to retouch parts that
have not assumed a sufficiently deep tint.
Instead of a bluing tray, a small mass of iron, with a slightly rounded
surface and heated to a suitable temperature, can be employed; but the
color must not form too rapidly, and this is liable to occur if the
temperature of the mass is excessive. Nor should this temperature be
unevenly distributed.
A spring after being whitened can be blued in the same way. Having
fixed one end, it is stretched by a weight attached to the other end,
and the hot iron is then passed along it at such a speed that a uniform
color is secured. Of course the hot iron might be fixed and the spring
passed over it. A lamp may be used, but its employment involves more
attention and dexterity.
=96.= =Bluing as an indication of temper.= This subject has already
been very fully considered in article =88= to =90=. When the color
assumed by a piece of steel does not require to be preserved, and it is
only necessary to temper the object at a certain temperature, the means
best adapted to expedite the operation will naturally be sought. Thus,
in factories, large numbers are tempered at once in a bath of tallow,
oil, etc. The workman, in judging temper by color (=88=), must have
enough experience to enable him to determine, for a given sample of
steel, what are the successive colors as well as the temperature of the
bath, etc. His success is certain; but it depends on the experience,
and, therefore, on the sense of sight of the operator, and, we should
again add, on the knowledge he possesses of the qualities of the steel
he is using.
CASE-HARDENING.
=97.= This process is often resorted to when a hard surface is required
on objects of wrought iron, for example the face of an anvil. It is
the exact converse of the method already described in article =59=
for obtaining malleable castings, and consists in heating the object
to a red heat in contact with charcoal, or some substance containing
carbon; this enters into the surface iron, converting it into steel.
Or after heating to a bright redness the object may be sprinkled over
with prussiate of potash, returned to the fire, and after a few minutes
cooled by immersion in water. When a greater thickness of steel is
needed, or when dealing with large articles, they must be enclosed in
wrought-iron boxes, and bedded in such substances as fragments of horn,
bones, leather cuttings, etc; the box is then luted up and the whole
maintained at a red heat for twelve hours, after which the fire is
allowed to die out. Articles may sometimes be case-hardened by coating
with a paste of arsenious acid, powdered leather, horn, or other
nitrogenous body and hydrochloric acid, and then heating them to bright
redness in a muffle or other suitable furnace.
INFLUENCE OF FOREIGN METALS AND METALLOIDS ON THE QUALITIES OF IRON AND
STEEL.
=98.= It would be impossible to give a full account of this subject in
the space at our disposal, and the reader must be referred to works
on the metallurgy of iron and steel for details in regard to the
remarkable influence of minute traces of phosphorus, tungsten, silicon,
manganese, arsenic, etc., on the mechanical and chemical properties of
those metals.
COPPER.
=99.= Copper is an elementary body of a reddish-brown color, which must
not be confounded with brass, occasionally termed yellow copper. In
tenacity it comes next below iron, breaking with a strain of 34 kilo.
per sq. mm. of section (or 48,000 lbs. per sq. inch).
In horology, the only use made of the pure metal is for the
construction of compensation pendulums on the gridiron principle, and
as wire in electric clocks. It is also employed, when rolled into thin
sheets, for a base to receive the enamel of watch dials, in consequence
of its expansion being about the same as that of the enamel, which does
not therefore crack in the cooling.
The copper of commerce is seldom pure, and this gives rise to many of
the imperfections met with in ordinary brass.
ZINC.
=100.= This is an elementary metallic body of a bluish white color. It
is used in the form of rods, for compensation pendulums.
It must be obtained of great purity, whether it is employed by itself
or to alloy with another metal. The presence of foreign bodies in zinc,
even in very small quantities, has a marked influence on the physical
properties of an alloy into which it enters.
The purer the metal the more easily will it roll, and this fact can be
taken advantage of as a test of quality.
Although very brittle at 0° C. (32° F.) and 200°C. (400° F.), it has
a maximum malleability at about 100° C. (212° F.), the boiling point
of water; it should, then, be heated to this degree before bending,
rolling, hammering, etc.
It may be annealed in boiling water, or by heating to such a
temperature that water hisses when allowed to drop on to it.
It melts at 420° C. (790° F.) and volatilizes if raised to a red heat.
A sudden cooling, or the presence of arsenic or antimony, will render
zinc brittle. It must not be melted in cast iron vessels, as the
quality of zinc is deteriorated by the small quantity of iron it takes
up under such circumstances.
This metal possesses a great affinity for oxygen, and therefore
oxidizes very readily when fused.
It is usual, before pouring zinc that is intended for rolling, to
throw some pieces of the solid metal into the molten mass, the object
being to somewhat reduce the temperature, and thus prevent a too rapid
cooling, as, in that case, zinc is very brittle.
BRASS.
=101.= Pure copper is difficult to work with the graver or file, but
such is not the case when this metal is alloyed with zinc; we then
obtain brass, or, as it is sometimes termed, yellow copper.
Alloys containing copper, zinc, and tin are termed bronzes.
If a small quantity of lead, about 1 per cent. of its weight, be added
to brass, it renders the metal less fibrous, imparting to it a certain
degree of brittleness so that it is more easily worked with the graver,
file, drill, or the saw.
When the brass is required to be hammered, a portion of the lead is
replaced by tin; by this means the metal becomes more malleable, or, in
terms of the workshop, soft.
The color, tenacity, ductility, malleability, etc., vary with the
percentage composition of the alloy. It is, then, of the utmost
importance that a watchmaker be able to test and select the brass
before employing it in his work; metal that is excellent for
wire-drawing, for example, would be utterly useless for making an
escape wheel, since it would become distorted in the cutting in
consequence of its ductility. It belongs, in fact, to the class of
metals that will extend under the hammer without hardening (very soft
brasses).
The following is given as an analysis of brass very frequently employed
in horology: copper, 66 per cent., zinc, 33 per cent.; and lead, 1
per cent. But it must not be forgotten that this is only to be taken
as a mean. Both the proportions and the qualities vary with different
makers, doubtless also according to the degree of purity of the metals
employed in their manufacture.
=102.= =To select brass.= By following the directions given below
any watchmaker should be able to select the brass best suited to his
special requirements.
When the copper is in excess, zinc being proportionately reduced, the
brass is usually soft and of a beautiful golden color. On the other
hand, as the proportion of zinc is increased, the brass becomes more
and more brittle, and at the same time, more fusible; the color changes
to a light yellow, ultimately becoming greyish-white, and brass of this
nature is said to be “hard.”
Very soft brass chokes the file, and spreads without hardening under
the hammer; very hard brass, on the other hand, is fragile, liable to
crack when hammered cold, and breaks in passing through the draw-plate.
Metal of a good yellow shade, intermediate between the golden and the
pale yellow color, passes well through the draw-plate, spreads out
slowly under the hammer, but without cracking, until of about half the
initial thickness, and then resists the further action of the hammer,
which rebounds from it; such brass is usually found to be of good
quality for watchwork.
A sheet of brass is rarely homogeneous. If, after pouring, the metal
has been allowed to cool slowly, the interior will be crystalline, and
there will be an uneven fracture. This will cause the tenacity, etc.,
to vary throughout the mass. Similar differences are occasionally to be
observed between the two faces of the same plate, due to the phenomenon
of _liquation_; that is to say, to a tendency that characterizes
certain metals when melted together to separate from one another when
the cooling is not affected under proper conditions.
If the two surfaces of a plate be scraped clean at several points, and
drops, as nearly equal as possible, of very pure watch oil, be placed
on these clean surfaces, it may be taken as a rough indication that
the metals are uniformly distributed if the successive shades of color
of the oil as time goes on are the same at all the points experimented
upon.
Some watchmakers heat the brass to a red heat (which must never be
exceeded), and plunge it into nitric acid (equal parts acid and water).
By this means the entire surface is cleaned, and the above examination
is facilitated.
HAMMER HARDENING OF BRASS.
=103.= =Plates.= The selection of the metal will depend on the purpose
for which it is intended, and the thickness must be such that, when
hammered till of sufficient hardness, it will approximately equal one
dimension of the required object; for it is advisable to remove as
little of the surface metal as possible, a plate always hardening much
more at the surface than in the interior.
There is considerable difficulty in indicating clearly in a book the
exact mode of conducting the operation of hammer-hardening, and the
assistance of a competent master is essential, at any rate for the
first few trials. It must suffice to point out that the anvil, with
a slightly convex surface, and the hammer, of sufficient weight, must
be in very good condition and, if possible, polished on their faces;
the head of the latter should be rather convex, and the pene or chisel
end somewhat broad and gently rounded off in all directions, for it
will be needed as a means of bending the metal upwards; the curvature
being such that there is not a danger of starting a crack, etc., by its
means. We have already spoken of these two tools (=79=, =80=); it is
only necessary to add that a thick straw pad should be placed under the
anvil or block.
When one is compelled to use brass that is too thick, so that there is
much work to be done with the hammer to reduce the thickness to what is
required, it is a good plan to commence by elongating the metal in one
direction, striking with the pene of the hammer a series of parallel
blows in the direction of the required elongation; when the thickness
is two or three times that ultimately needed, the surface is smoothed
with the hammer-head and annealed; then it is brought to the right
thickness by another hammering in the manner explained below, but it
should be again pointed out that, when possible, metal of a suitable
thickness ought to be taken in the first instance, since too much
hammering has a detrimental effect.
Before hammer-hardening a plate, it must be dressed, an operation which
consists in rounding off the edges very carefully in order to prevent
their cracking, and in rounding the bottom and sides of internal angles
which, without such a precaution would occasion a rupture. After this
is completed, proceed to the hardening, using a rather heavy hammer,
and giving sharp blows along lines parallel to the sides of the plate;
commence from one of the corners in the case of a square plate; and
with a round plate let the blows be in circles. In the latter case,
work from the circumference towards the center, at the same time
gradually increasing the force of the blows, since the metal opposes a
greater resistance towards the center. If the work is done evenly and
without hurrying, the surface will remain fairly flat, a fact which
should be verified from time to time by the aid of a metal rule.
Round plates are sometimes hardened by commencing to hammer in the
center and working towards the circumference along two radii in
opposite directions; that is along a diameter. This first diameter
is then crossed by another at right angles; the intervals are filled
in with other diameters that must not touch until the entire surface
is covered, always taking care to work from the center towards the
circumference.
When the metal is thin only the hammer-head is used, but beyond a
certain thickness the pene of the hammer must be employed until about
half the required thickness is reached; the surface is planished and
the hardening finished with the face.
Blows that are irregular, too hard or roughly given, will cause the
metal to crack. Hurried working will disturb the molecular grouping
of the alloy; it will at the same time be heated and therefore
softened, thus losing all the good qualities that are anticipated from
hammer-hardening, namely increased body and elasticity. It was in order
to avoid this heating that the old watchmakers used to hammer the brass
in cold water, an excellent precaution which is too much neglected at
the present day.
Brass that is badly hammered, the blows being violent or irregular,
will spring out of shape on being cut and occasionally crack when
gilding.
If during the process of hammering, a crack is observed to be
commencing at the edge, it must be removed with a rat-tail file, all
sharp angles being rounded off; and when cracks immediately reappear
on continuing the operation, it is an indication that the metal cannot
support any further hammering cold.
If brass is compact or well forged it may be relied upon to preserve
the oil at pivots, etc., better, as oil is decomposed more rapidly in
presence of a finely divided metal.
=104.= =Brass rods.= Rods having a square section must only be hammered
on two opposite faces.
A rod of square section can be hammered on all four faces but it must
be first filed perfectly square; the hammering must not be pushed too
far, and the four angles must be maintained right angles. If some are
made obtuse and others acute, a flaw will be produced in the direction
of a diagonal.
The three following methods are employed in the case of round rods:
The first consists in hammering over the entire surface, the rod being
at the same time rotated on the anvil by hand; but this operation must
not be much prolonged, as the metal is liable to crack lengthwise.
The second method consists in reducing the diameter of an annealed
brass rod to about one-half or two-thirds its initial amount by causing
it to pass in succession through a number of holes of the draw-plate.
When the third method, which is due to Brocot, is adopted, one
extremity of the brass rod is gripped in the bench vise and the other
end in a hand vise, which is then caused to rotate round the rod as
an axis. If the torsion be continued until the metal is on the point
of breaking, it will be found to be very effectually hardened. This
method is resorted to with advantage for hardening pin-wire and the
metal for making pillars.
TO ANNEAL BRASS.
=105.= When it is necessary to considerably reduce the dimensions of a
piece of brass, either with the hammer, rolls or draw-plate, it must be
annealed from time to time.
The metal should not be heated to redness; it is supposed, rightly or
wrongly, that such a proceedings especially if repeated, separates
a portion of the zinc, or at least changes the mode in which it
is associated with the copper. Brass should be heated slowly and
uniformly, in a moderate fire, until the temperature is such that drops
of water thrown onto the surface are rapidly converted into vapour, or
paper turns yellow and begins to smoke. It is then withdrawn from the
fire and allowed to cool.
Brass is brittle when hot, so that it can only be worked cold.
When brass is annealed, just as when steel is tempered, the metal
should not be allowed to rest on a bad conductor of heat, such as wood
or stone, because there will be a tendency to uneven distribution of
the heat throughout the metal.
CAST BRASS.
=106.= This is usually brittle, owing to the fact that the copper
employed in its manufacture consists, as a rule, of all sorts of
scrap, from good or bad metal; moreover, from motives of economy,
the proportion of zinc is generally increased and, in pouring, the
precautions essential to avoid the effects of liquation (=102=), etc.,
are frequently neglected. Such an alloy must never be used for small
objects, it must be entirely excluded from a watch, and in a clock only
such pivots as are called upon to perform an insignificant amount of
work should be allowed to run in it.
In order to avoid injuring the file, or embedding in the metal any
particles of the hard coating of oxide that always covers rough
castings, it is usual to dip the object in dilute nitric or sulphuric
acid (=155=), by which the oxide is dissolved.
TIN.
=107.= This is an elementary body, almost as white as silver and having
a breaking strain of only 8 kilo. per sq. mm. of section (or 11,300
lbs. per sq. inch.)
Watchmakers use it in making solder. It is also sometimes used in the
form of plates or rods for polishing with rouge, and it is said to be
much more efficient when very pure.
If a strip of pure tin is bent, a crackling noise, termed the “crying”
of tin, is heard. After frequent bending, the metal loses this property.
The degree of purity may be judged:
(1) By the loudness of the “cry,” which is found to be greater as the
tin is purer;
(2) By the relative lightness of two balls of equal size, one of which
is formed of very pure tin and used as a standard;
(3) By pouring the metal, when just melted, in a mould 1 or 2
centimetres (about ¾ inch) in diameter. If tin is pure, when cast
into plates or ingots, the surface will be perfectly smooth, without
exhibiting any sign of crystallization at the moment of solidification,
whereas the presence of small quantities of foreign metals causes it to
be covered with a network of needle-formed crystals, which are the more
numerous according as the metal is less pure.
The Banca tin is almost chemically pure; English tin is also very pure;
but others contain a small percentage of copper, lead, iron, or arsenic.
BRONZE.
=108.= Bronze is an alloy, in very variable proportions, of copper
and tin, to which may be added, according to circumstances, a small
percentage of lead or zinc, or even iron, when it is desired to
increase the hardness or tenacity.
As a rule, this alloy is tough and hard to work; it is especially used
for parts of large machines that are subjected to considerable pressure.
The fusion and casting of bronze require special precautions, for the
proportion between the metals is liable to vary through oxidation of
the tin, which then goes to form a dross, and the composition may
vary throughout the mass. It sometimes results from this that the
bronze bearings for the pivots in large clocks are not even as good as
ordinary brass, and wear away more rapidly than the pivots.
Bronze is also used by watchmakers for making plates or small rods
for polishers, and for the bells of clocks. Bell-metal contains about
78 per cent. of copper and 22 per cent. of tin; it has a beautiful
fracture, and is very fusible and sonorous. The addition of any other
metal is rather prejudicial than otherwise; this explains why so many
clock bells are wanting in sonorousness.
An impediment to the use of bronze is its want of malleability; but
Dronier has recently pointed out that such alloys may be rendered
perfectly ductile and malleable by adding from ½ to 2 per cent. of
mercury. These alloys are said to be less oxidizable than ordinary
bronzes, and at the same time more hard, elastic, resisting and
sonorous.
STERRO.
=109.= This is an alloy containing 56 per cent copper, 41 zinc, 2 tin
and 1 iron. It resembles a reddish-colored brass, and has been much
used in Vienna, where it is considered superior to brass from the point
of view of ductility, tenacity and malleability.
An experienced horologist, M. Grossmann, made satisfactory lever
escape-wheels of it, and he considers it to be superior to the best
brass in regard to both density and elasticity. At the same time he
points out that it clogs the cutter, and the color is inferior to that
of good hard brass.
LEAD.
=110.= A metal with a brilliant bluish grey lustre, which rapidly
becomes dull when exposed to the air. It is very malleable and ductile.
It breaks with a strain of 2.9 kilo. per sq. mm. section (4,000 lbs.
per sq. inch), but possesses extreme flexibility.
Lead is not used in horology, except as a constituent of solders; in
these, however, it plays a very important part. It is occasionally
used in the pure state as a lap for applying polishing materials, but
more frequently alloyed with tin, by which hardness is imparted to the
metal, the alloy being known as “pewter.”
NICKEL.
=111.= An elementary metallic body of a greyish-white color, resembling
that of platinum. With care it can be forged when hot and formed into
plates; its structure in that case is fibrous. Its hardness is the same
as that of iron, and nickel will take a high polish. Next to iron, it
is the most powerfully magnetic of all metals.
It can be caused to alloy with many other metals—notably iron, cobalt,
copper, zinc, tin, and antimony. According to Stodart and Faraday,
an alloy of 33 parts iron and 1 part nickel is as malleable as the
former metal, but less liable to rust. Fleitmann has recently shown
that by the addition of about 1-10th per cent of magnesium, nickel is
rendered perfectly malleable and ductile, capable of being drawn into
wires or rolled into sheets, and Garnier finds that 3-10ths per cent of
phosphorus has a similar effect.
Nickel is useful as a coating for objects that are not subjected to
friction, for preserving them from the action of the air. It takes a
beautiful polish, and is not tarnished by being touched.
GERMAN SILVER.
=112.= Although the proportion of copper in this alloy is considerably
greater than that of nickel, watchmakers frequently apply the latter
name to it, doubtless on account of the beautiful polish of which the
metal is capable and the comparative inoxidizability which it derives
from the presence of nickel.
German silver is an alloy of copper, nickel and zinc, with the
occasional admixture of a small proportion of iron or tin. When used in
the construction of objects that require soldering, 2 per cent. of lead
is added.
The alloy usually employed in horology is very malleable; it has a mean
composition: copper, 60 per cent; nickel, 20 per cent; and zinc, 20 per
cent. That containing 58 per cent copper, 14 nickel, 25 zinc, and 3
iron, is said to be highly elastic.
The following useful details with regard to the employment of German
silver for watchwork are due to M. C. E. Jacot.
Watch movements have been made of this alloy for the past thirty years;
it was long thought that the taste would die out, but, on the other
hand, the demand for “nickel” movements increases each year.
The alloy is better prepared at the present day; it has a beautiful
grayish-white colour, it is more malleable, and better to work than
formerly, but still not so easy as brass. The latter alloy is less
detrimental to the file, and can be turned and drilled more rapidly.
German silver is only used for the plates, cocks and bars. The barrels
and wheels are of brass, and surfaces exposed to friction, such as the
center pivot-hole (all other holes being jewelled) are bushed with
the same metal, for it is observed that in presence of nickel oil is
rapidly blackened and the pivots wear sooner than when working in good
brass.
The color remains unaltered for a long time if the surface has been
carefully smoothed in the first instance; and if cleansed with soap and
water, its original freshness can be to a great extent restored. Some
watchmakers prefer to employ chemical preparations for cleaning the
metal.
The following is recommended as very effective for this purpose: Mix 50
parts alcohol, 1 part sulphuric, and one part nitric acid. Allow the
pieces to remain in this liquid for 10 or 15 seconds, wash with cold
water, and subsequently with alcohol, dry with a soft rag or in boxwood
saw dust.
GOLD.
=113.= An elementary body, the most beautiful and the most valuable of
all the ordinary metals. In the unalloyed state it has a pure yellow
color, and when reduced to extremely thin leaves, appears green by
transmitted light. It is the most malleable and ductile of all the
metals, but its tenacity is low.
Gold resembles platinum, silver, iron, etc., in being capable of
welding, that is to say, two pieces of the metal can be united without
previous fusion. Indeed, by the application of great pressure it can be
made to weld when cold.
It is insoluble except in aqua regia (a mixture of 1 part nitric acid
and 4 parts hydrochloric acid), alkaline persulphides and selenic acid.
Chlorine, phosphorus, and a few other substances can be made to combine
with it by the acid of heat.
It is as a preservative, that is applied in layers termed “gilding,”
that gold is principally used in watchwork, and some details will be
found on this subject under “Gilding,” (articles =142=-=153=). Owing to
its softness the metal is not used in a pure state, but usually alloyed
with copper. The principal alloys in use in this country are:
22 parts (carats) gold, 2 parts (carats) copper, for coin and wedding
rings.
18 parts gold, 6 parts copper, for high-class jewelry and watch-cases.
15 parts gold, 9 parts copper, for ordinary jewelry.
12 parts gold, 12 parts copper; and 9 parts gold, 15 parts copper, for
common jewelry.
The alloys used for soldering gold will be described under “Solders”
(=126=).
Alloys of gold with silver and copper have been employed for making
watch wheels; they wear well, and will take a beautiful polish, which
is maintained for a longer time than in the case of brass wheels.
Chronometer balance-springs and the suspension-springs for astronomical
clocks have also been made of gold-copper or gold-silver alloys rolled
and hardened (=591=.) If carefully prepared, they maintain their
elasticity unimpaired for a long period, and there is no liability to
rust.
The dilatation for a given change of temperature is, however, greater
than that of steel, so that a greater compensating effect becomes
necessary, but this inconvenience is partially compensated for by its
inoxidizability and the fact that it is not liable to become magnetic.
SILVER.
=114.= This metal in an unalloyed state is too soft for use in
horology; its principal use is for cases, and as a constituent of
solders.
Houriet made watch wheels of an alloy containing 2 parts silver to 1
part 18-carat gold, and he affirmed that this alloy became polished at
the acting surfaces of the teeth. Jurgensen states that chronometer
escape-wheels made of this alloy, carefully hammered, do not require
oil at the points of their teeth.
Dumesnil proposed an alloy of 2 parts copper, 1 part silver, and 1 part
zinc, all perfectly pure. Lecocq made chronometer balances in which the
brass was replaced by pure silver deposited on the surface of the steel
by electrolysis, thus avoiding the use of a fire. The compensation is
said to have been very efficient.
ALUMINIUM AND ALUMINIUM BRONZE.
=115.= Aluminium is an extremely light elementary body, having a
density of only 2.56; with equal bulks, therefore, it will weigh only
about as quarter as much as silver. As its capacity for heat is very
great, this metal is observed to heat or cool more slowly than other
metals.
Pure, or in a slightly alloyed state, it has not been used in horology,
except for pendulum rods and large hands in regulator clocks; in short,
it can be employed where lightness is the principal quality in view.
It is extremely ductile. The presence of 1-100th part of bismuth,
however, renders the metal somewhat brittle, and it develops cracks
under the hammer. Traces of iron also decrease its malleability.
An alloy of 5 parts silver and 95 aluminium can be as easily worked as
the pure metal, but is harder and takes a better polish.
We would add a curious observation of M. Redier: After passing a piece
of aluminium several times through the draw-plate, he observed that the
elongation had only occurred at the surface; for on cutting the wire at
different points, he noticed that, throughout a portion of the length,
the metal was hollow, a very fine capillary tube being thus formed.
=116.= _Aluminium Bronze_ is an alloy of aluminium with copper. A
alloy of 5 parts of the former to 95 of the latter has a beautiful
golden color, but if the proportion is changed to 10 and 90 parts
respectively, we obtain the most serviceable and the most easily worked
alloy.
This bronze can be forged at a cherry-red heat, and even near its
melting point; and its thickness can be reduced to a very small amount
under the hammer. It is easily filed and turned, but does not possess
any special advantage over brass, which is less detrimental to the
file; the density is 7.7, very little below that of brass, 8.4.
It appears from a considerable number of experiments that it might
be used with advantage for the bearings of axes that rotate with
high velocities. It resists wear better than any other metal. In the
experiments made by Foucault to demonstrate the rotation of the earth
by means of the pendulum, he found that an aluminum bronze wire lasted
for the longest period. Its tenacity is equal to that of iron. It has
been shown that slide-bars of locomotives made of this bronze resist
wear twice as long as those formed of the ordinary bronze. There would
then be an advantage in using it for the bearings of foot-lathes, etc.
Grossman asserts that lever escape-wheels of this metal have proved
satisfactory, and he makes the following observation on the subject. If
aluminium bronze be reduced to three-fourths of its original thickness
by hammering, it will begin to crack. This can be prevented by heating
to a red heat and plunging into water; it can then be again reduced by
one-fourth of its thickness, and again annealed, and so on. He reduced
the thickness from 2.5 millimeter to 0.2 millimeter, and the metal
resisted for a long period repeated flexures backwards and forwards;
and he observes that no other metal, after being so much compressed,
would possess the same marvellous degree of tenacity.
In order to obtain aluminium bronze of the best quality, the copper
should be absolutely pure, and, in the manufacture, the alloy must be
melted and forged two or three times in succession, as by this means
the strength and tenacity are increased, and the metal can be more
easily worked.
The beautiful golden color possessed by certain of these bronzes when
polished, has caused them to be used for cheap watch-cases, but they
always tarnish at those parts that are not subject to daily wear.
MERCURY.
=117.= This is the only metal liquid at the ordinary temperature; it
solidifies at -40° C. (-40° F.). It possesses a high metallic lustre,
resembling silver, but with a slightly bluish tint, and does not
oxidize at ordinary temperatures.
Mercury alloys with many other metals, forming amalgams, and as small
a quantity as 1-40th per cent of lead suffices to entirely alter its
character. The presence of such traces can be easily detected by the
liquid wetting glass or china, and therefore forming a tail when a
vessel containing it is tilted.
The commercial metal is rarely pure, but the greater portion of the
lead, tin, bismuth or copper, by which it is contaminated, can be
removed by distillation. The most convenient method consists, however,
in agitating the metal with either dilute nitric acid, a solution of
mercurous nitrate, strong sulphuric acid, a solution of corrosive
sublimate or of perchloride of iron, and subsequent washing with
distilled water. When mercury is only contaminated with mechanical
impurities, they can be very effectually removed by agitating with
powdered loaf sugar.
This metal has many uses in the arts, for the construction of
thermometers, barometers; for plating, etc.; in horology it is used
for compensation pendulums, and has also been occasionally used for
compensation balances.
PLATINUM.
=118.= This elementary body is almost as white as silver, takes a
brilliant polish, and is highly ductile and malleable. It is the
heaviest of the ordinary metals, the least expansive when heated, and
has a breaking strain of 40 kilo. per sq. mm. section (56,500 lbs. per
sq. inch.).
Platinum is infusible, except at the high temperatures attainable with
the oxy-hydrogen blow-pipe. At a white heat, however, it softens,
and can be forged and welded. It is unacted upon by the air at any
temperature, and is insoluble in acids, except aqua regia (=155=),
although acted on by certain alkalies.
This metal is used in the construction of scientific instruments, and
for objects that are exposed to the air, as, for example, sun dials.
Alloyed with irridium, (a rare metal of the same group) it possesses an
excellent and unalterable surface for fine engraving, as the scales of
astronomical instruments, etc. This alloy has also been adopted for the
construction of international standards of length and weight.
Platinum is much employed for chemical apparatus, in consequence of its
being unacted on by acids, and its non-liability to melt in ordinary
furnaces. Both the pure metal and its alloys with silver have been
employed in the form of wire for bushing the pivot-holes of watches,
and in sheets for cutting out cocks and wheels, but the results
obtained were not as good as with good brass. As a rule, such wheels
are found to occasion a rapid wear of pinion leaves.
Attempts have also been made to construct balance-springs of this
metal, but we are informed that they were not found to possess any
sufficient advantages.
It is advisable to heat platinum in a spirit lamp or Bunsen burner; the
naked flame is objectionable, because, being charged with a certain
amount of carbon, it deteriorates the metal.
PALLADIUM.
=119.= This metal resembles silver rather than platinum, and is almost
as infusible as the latter metal. It has a density of 12.5. When heated
in contact with air it becomes blue, owing to the formation of an
oxide. It possesses the remarkable power of absorbing (or _occluding_)
about 900 times its own volume of hydrogen, if attached to the negative
pole of a battery in acidulated water; its bulk is increased slightly
by this charge, and, on expelling the gas by the aid of heat, the
metal shrinks to less than its initial dimensions. Palladium is useful
for the graduated scales of scientific instruments, since it is not
discolored by sulphurous acid. It forms alloys with most of the metals
and some of these can be hardened like steel. If 100 parts of steel be
alloyed with 1 part of this metal, the resulting alloy is said to be
excellent for making scientific instruments, and an alloy of 24 parts
palladium, 44 silver, 72 gold, and 92 copper has been recommended for
use in horology.
M. Paillard, of Geneva, has introduced balance-springs made of an
alloy, whose composition is not given, possessing the following
advantages: they are non-magnetic, their tenacity is considerable, are
not tarnished by the air, sulphurous acid, or sea water; nor are they
distorted by heating, and, on cooling, they recover their original
elasticity, which is equal to that of steel hardened and tempered to a
blue color. The co-efficient of expansion of this alloy is rather less
than that of steel.
CHARACTERISTIC PROPERTIES OF ALLOYS.
=120.= _Density._ This is sometimes rather greater and sometimes less
than that deduced from the densities of the constituent metals,[4] but
no exact law has been discovered in regard to this question.
_Hardness, Ductility, Tenacity._ Alloys are usually harder, more
brittle, and less ductile and tenacious than the most ductile and
tenacious constituent metal.
_Elasticity._ The co-efficient of elasticity of an alloy generally
approximates closely to the mean of the co-efficients of its
constituent metals.
_Expansion._ The co-efficient of linear expansion of an alloy, that is
to say, the number representing the proportional part of its length
by which it increases for each degree rise of temperature, may be
approximately estimated as follows: multiply the linear co-efficient of
each constituent metal by the percentage of it present in the alloy,
and divide by its density. Add together the several numbers thus
obtained. Multiply this sum by the density of the alloy (which must be
experimentally determined) and divide by 100. The resulting figure is
the required linear co-efficient (=122=).
_Fusibility._ Alloys are always more fusible than the least fusible of
their component metals, and often more so than any one of them.
_Oxidation._ As a rule, the air acts with less energy on alloys than
on their constituent metals. There are, however, cases in which the
converse is the case.
_Action of acids._ This is generally similar to the action on the
predominating metal.
_Observations._ Alloys formed of metals that differ materially in
density are rarely homogeneous, especially if they have been allowed
to cool slowly. It is, then, essential that they be thoroughly stirred
and cooled rapidly. It is for this reason that alloys are frequently
poured out on to a flagstone to cool, or that they are compressed after
pouring, whereby the formation of crystals is prevented.
=121.= =Metals and alloys.= The following table gives the more
important physical properties of the metals and alloys generally met
with, and will be found useful for reference. The precise meaning of
each number may be gathered from the notes in paragraph =122=.
+-------------------+------------+----------+-----------------------+
| | Specific | Degree | Linear Expansion |
| METALS. | Gravity. | of | per |
| | (Water=1) | Hardness | 1° Fahr. 1° Cent. |
+-------------------+------------+----------+-----------+-----------+
|Aluminium (115) | 2.56 | -- | 0.0000123 | 0.0000222 |
| ” Bronze (116)| 7.7 | -- | -- | -- |
|Brass, Drawn (101) | 8.54 | -- | 0.0000107 | 0.0000193 |
| ” Cast (106) | 8.10 | -- | 0.0000104 | 0.0000187 |
|Bronze (108) | 8.40 | -- | 0.0000100 | 0.0000180 |
|Copper (99) | 8.94 | 2.5-3 | 0.0000102 | 0.0000183 |
|German Silver (112)| -- | -- | -- | -- |
|Gold (113) | 19.26 | 2.5-3 | 0.0000077 | 0.0000138 |
|Iron, Wrought (54) | 7.84 | 4.5 | 0.0000066 | 0.0000119 |
| ” Cast (58) | 6.9 to 7.5 | -- | 0.0000062 | 0.0000112 |
|Lead (110) | 11.33 | 1.5 | 0.0000167 | 0.0000301 |
|Mercury (117) | 15.60 | -- | 0.000101 | 0.000182 |
|Nickel (111) | 8.82 | 5 | [cubical | [cubical |
|Palladium (119) | 11.80 | 4.5-5 | -- | -- |
|Platinum (118) | 21.50 | 4-4.5 | 0.000005 | 0.000009 |
|Silver (114) | 10.57 | 2.5-3 | 0.0000111 | 0.0000190 |
|Steel (60) | 7.72 | 6-7(hard)| 0.0000057 | 0.0000103 |
|Sterro (109) | -- | -- | -- | -- |
|Tin (107) | 7.30 | 2.5-3 | 0.0000152 | 0.0000273 |
|Zinc (100) | 7.13 | 2 | 0.0000122 | 0.0000220 |
+-------------------+------------+----------+-----------+-----------+
+-------------------+---------------+---------+---------------------+
| | Specific Heat | Melting | Conductivity |
| METALS. | per Degree | Point. | for |
| | Cent. | | Heat. Electricity. |
+-------------------+---------------+---------+--------+------------+
|Aluminium (115) | 0.2143 | 1500° F.| -- | 56.1 |
| ” Bronze (116)| -- | [about| -- | -- |
|Brass, Drawn (101) | } 0.0939 | { -- | -- | -- |
| ” Cast (106) | } | { 1870° | -- | -- |
|Bronze (108) | -- | 1692° | -- | -- |
|Copper (99) | 0.0951 | 2000° | 73.5 | 99.8 |
|German Silver (112)| -- | -- | -- | 7.67 |
|Gold (113) | 0.0324 | 2610° | 53.2 | 78.4 |
|Iron, Wrought (54) | 0.1138 | 2900° | 11.9 | 16.8 |
| ” Cast (58) | 0.1298 | 1920° | -- | -- |
|Lead (110) | 0.0314 | 608° | 8.5 | 8.3 |
|Mercury (117) | 0.0333 | 39° | -- | -- |
|Nickel (111) | 0.1086 | -- | -- | 13.1 |
|Palladium (119) | 0.0593 | -- | 6.3 | 18.4 |
|Platinum (118) | 0.0324 | -- | 8.4 | 18.0 |
|Silver (114) | 0.0570 | 1832° | 100.0 | 100.0 |
|Steel (60) | 0.1175 | 2400° | -- | -- |
|Sterro (109) | -- | -- | -- | -- |
|Tin (107) | 0.0569 | 446° | -- | 12.4 |
|Zinc (100) | 0.0955 | 680° | -- | 29.0 |
+-------------------+---------------+---------+--------+------------+
=122.= =Notes on the foregoing table.= For a complete explanation of
the several properties of metals and alloys that are enumerated in the
above table, the reader must be referred to works on mechanics and
physics, but the following explanatory notes are necessary.
The number in brackets after the name of each metal, etc., refers to
the article in which it is considered.
The _specific gravity_ of a substance is the ratio of the weight of a
given bulk of that substance to the weight of the same bulk of water at
a definite temperature. The numbers here given can only be regarded as
approximations, as the specific gravity varies greatly with the state
in which a body exists, the hammering it may have been subjected to,
etc.
_Degree of hardness_ is ascertained by means of the following standard
series, observing which of them scratches the body under examination
and which it is capable of scratching.
1, Talc; 2, Gypsum; 3, Calc-spar; 4, Fluor-spar; 5, Apatite; 6,
Felspar; 7, Quartz; 8, Topaz; 9, Sapphire; 10, Diamond.
_Linear expansion._ These co-efficients represent the extension in
length that the several substances undergo when heated: the first
column for each degree Fahrenheit and the second for each degree
Centigrade. The extension is given per unit of length; thus, 1 inch of
copper at 32° F. will become 1 + 0.0000102, or 1.0000102 inch at 33° F.;
and 1 + 30 × .0000102, or 1.000306 at 32 + 30 or 62° F.
Superficial expansion may be obtained by multiplying the linear
co-efficient by 2, and cubical expansion by multiplying the same number
by 3.
As in the case of specific gravity, these data, as well as those in
succeeding columns, can only be regarded as approximations, depending
on the condition of the metal etc.
_Specific heat_ is the amount of heat required to raise the temperature
of a substance one degree (the Centigrade scale being here adopted),
that required for the same weight of water being taken as unity. The
corresponding numbers on the Fahrenheit scale can be deduced from those
here given by multiplying by 5 and dividing by 9.
The _melting points_ are given on Fahrenheit’s scale and can only be
regarded as approximate on account of the difficulty experienced in
determining these high temperatures. Different observers often vary by
two or three hundred degrees in their estimates.
_Conductivity for heat and electricity_ are given in reference to that
of silver, which is called 100. It surpasses all other known metals in
both these properties when chemically pure, but a trace of impurity has
a very prejudicial influence on them.
It will be observed that in many cases the conductivities have not been
determined, a remark that applies to other columns of the table.
SOLDERING.
=123.= It is well known that a _solder_ is an alloy employed to unite,
by the aid of heat, two metallic bodies that are placed in contact.
A solder, then, must be much more fusible than the metals it unites,
otherwise these latter would be damaged by the degree of heat applied.
Solder is all the less tenacious, and melts the more easily according
as the proportion of the most fusible metal present is increased.
This fact is taken advantage of when several solderings have to be
performed on the same object. The alloy last employed will require to
be considerably more fusible than the first, as otherwise the heat
would be so great that the earlier joints would melt. In an ordinary
lead-tin solder, the fusibility is increased by increasing the
proportion of the latter metal till the lead is to tin, as 6 is to 1.
This alloy melts at 194° C. (380° F.), and the melting point may be
still further reduced by adding a gradually increasing proportion of
bismuth.
As the melting point of the solder approximates to that of the metals
to be united, the risk of damaging these latter is of course increased,
but, at the same time, the joint will be all the stronger, as the metal
will be almost as strong there as at any other point, and it can be
forged, etc.
Solders are distinguished as _hard_ or _soft_; the former requires
the application of a red heat, and can therefore only be used for
such metals as gold, silver, brass; whereas the latter melt at very
low temperature, and can be employed for metals that have low melting
points, or when it is important not to exceed a moderate degree of
heat. The joint is, however, the more solid according as the heat
employed approximates to that at which the metal will melt.
=124.= =Composition of solders.= The solders ordinarily employed can
be obtained from material dealers, but it is advisable to give here
the composition of some of the more important, specifying the metal to
which they are applicable.
=125.= _Aluminium solders._ I. Zinc, 70 parts; copper, 15; aluminium,
15.
II. M. Mourey employes a series of aluminium-zinc alloys, commencing
with two per cent aluminium to 98 per cent zinc, and progressing to 20
per cent of the former to 80 per cent of the latter metal.
=126.= _Gold solders._ I. Gold, 6 parts; copper, 1 part; silver, 2
parts.
II. Gold, 15 parts; silver, 2 parts; copper, 1 part.
III. Gold, 11.94 parts; silver, 54.74 parts; copper, 28.17 parts; zinc,
5.81 parts. The three first metals are melted together in a crucible,
and when they have somewhat cooled, a rather greater proportion of zinc
than is here indicated (to allow for loss by volatilization) is added,
and the alloy constantly stirred.
=127.= _Silver solders._ I. Silver, 2 parts; brass (for pin-wire), 1
part.
II. Silver, 5 parts; pin-wire brass, 1 part.
III. Silver, 10 parts; pin-wire brass, 5 parts; pure zinc, 1 part.
=128.= _Tin solders._ I. (ordinary soft solder.) Tin, 2 parts; lead, 1
part.
II. (Harder, and known as “Plumbers’ Sealed” solder.) Tin, 1 part;
lead, 2 parts.
III. Many other proportions of tin and lead are occasionally used,
ranging from tin, 1 part; lead, 25 parts, to tin, 6 parts; lead, 1 part.
IV. (Very fusible solder, melting in boiling water.) Lead, 3 parts;
tin, 5 parts; bismuth, 8 parts. The fusibility is still further
increased by adding mercury or cadmium.
=129.= _Spelter solders._ (Used for brazing.) Copper and zinc in
varying proportions. It becomes more fusible as the amount of zinc
present is increased.
METHODS OF SOLDERING.
=130.= A thorough cleansing of the surfaces to be united is always
needful, but more especially so in the case of soft soldering. It may
be effected by means of acids, or with a graver or scraper, etc.;
the cleansed surfaces must not be touched with the fingers, and the
soldering should be done at once. If acids are employed, the objects
should be thoroughly washed after soldering, in order to avoid rust;
and, after drying, they should be rinsed with alcohol.
The parts to be soldered are held in position with clamps, tweezers,
pins, or iron wire. This latter, known as _binding wire_, is used for
delicate objects and should be very pliable. When a high degree of heat
is to be applied, all risk of the iron uniting with gold may be avoided
by mixing a little sandiver with the borax employed. (See article
=153=).
Before heating, if there are already parts united with solder, they
should be covered with borax to prevent softening.
Only a moderate heat should at first be applied, so as to melt the
borax, or sal-ammoniac without displacing it. The violent frothing up,
which is very liable to displace the parts or the fragments of solder,
can thus in a great part be avoided. If a naked lamp-flame is used,
or if it is directed on to the object with a blow-pipe, it should
be, so to speak, large and soft, and the jet should not be directed
to the point of juncture until the solder is observed to have fused.
In soldering brass to steel, it is sometimes necessary to direct the
flame against the brass only, in order, as far as possible, to avoid
softening the steel. The hard solders for gold, silver, etc., require
a considerable degree of heat, so that the objects must be heated to
redness.
=131.= =To solder gold and platinum= to each other or to themselves.
On a hard wetted surface, marble, for example, rub a piece of borax
until a white liquid paste is obtained (or the powdered borax sold by
chemists can be made into paste direct). Having prepared the borax, the
surfaces to be united are cleansed either by scraping or with dilute
nitric acid (=155=); the acid may be previously heated to boiling,
as it will then act more rapidly; and the surfaces are subsequently
scraped. They are now covered with the borax with a paint brush, set in
position, and small pieces of solder placed on the junction. As already
observed, the heating must at first be gentle to avoid displacing the
solder by the frothing of the borax.
=132.= =To solder silver.= Also for uniting gold to silver, or silver,
brass, steel to each other or to themselves. Proceed in the manner
already explained for gold and platinum, except that the borax paste
must be sensibly thicker.
=133.= =To solder tin.= Also for uniting gold, silver, brass to each
other, or to other metals, such as steel, iron, etc. Clean the surface
with a graver or scraper; sulphuric or hydrochloric acid may be used,
but in this case the cleansing afterwards must not be forgotten.
The heating is effected as in soldering gold, unless a soldering iron
is used, when the directions subsequently given should be followed.
=134.= =To solder aluminium.= M. Mourey recommends the following method.
One of the series of aluminium solders, No. II. (art. =125=), is
employed and, as a flux, two-thirds of balsam of copaiba, one-third
very pure Venice turpentine, and a few drops of the juice of a citron;
these constituents are pounded together in order to secure a perfect
admixture.
The surfaces to be united are covered with solder (employing a
soldering iron of aluminium) just as in the case of tinning (=137=),
the flux just mentioned being used. The two surfaces, thus prepared,
are placed in contact and maintained in the required position, and,
after laying on the joint particles of solder that are richer in
aluminium than the one used for preparing the surfaces, the whole is
placed over a charcoal fire or heated before the blow-pipe, pressing
gently on the pieces of solder, which will soon melt and should be
distributed by means of a little tool of aluminium.
During this second stage of the process, it is necessary to be very
cautious in the application of the flux; the pieces of solder should
only be dipped in it before being placed in position, for the flux is
mainly for use in preparing the surfaces; as soon as the solder has run
well, the temperature should be lowered in order not to dry up and burn
the solder, which would be apt to become brittle.
In preparing the solders, the aluminium is first fused and stirred with
a small iron rod; then add the zinc and stir again; add a little tallow
and cast the solder into rods.
The zinc must not be too much heated, as it will volatilize, leaving
the alloy rich in aluminium and therefore brittle.
=135.= =Fluxes for soldering.= Various substances can be employed as
fluxes for cleansing the surfaces to be united:
_Sal-ammoniac_ reduced to powder and made into a paste with sweet
oil, or merely dissolved in water. A paste formed of _sal-ammoniac_
and _resin_, reduced to powder, with water or oil. _Resin_ alone will
suffice for the soft soldering of copper or brass. _Venice turpentine_,
which has the advantage of not causing steel to rust, although it
makes the objects sticky so that they require to be afterwards rinsed
in alcohol or turpentine.
Various acid solutions are sold for the purpose and experience will
enable the watchmaker to select that which is best adapted to his
requirements.
Lastly, saturated _chloride of zinc_ can be recommended. It is prepared
as follows:
Some dilute hydrochloric acid (which also goes by the name of spirits
of salts, or muriatic acid) is placed in a glass flask and strips of
zinc are added one by one; the flask must be left uncorked and the zinc
added a little at a time, lest the effervescence that occurs should
break the vessel. When the zinc added is not acted on by the fluid
it may be concluded that the acid is saturated or “killed,” and the
fluid may then be transferred to a stoppered or corked bottle for use.
In using it, a small quantity is spread over the surfaces that are
to be united and the solder will be found to run with great freedom.
Some authorities recommend the addition of sal-ammoniac to the extent
of one-fourth the weight of acid taken. It is well again to warn the
reader that the pieces must be thoroughly washed after employing these
liquids, for, otherwise, they will cause tools with which they are
brought in contact to rust and will rust themselves if they consist
wholly or in part of iron or steel. The vessel containing the fluid
must be kept well away from the work-bench.
The liquid can be used immediately after being prepared as above
explained; but all acid reaction may be prevented by evaporating at
a moderate temperature until of the consistency of oil; it is then
allowed to cool and kept in a bottle.
=136.= =The soldering iron= with a head of copper, such as is used
by tin-plate workers, is well known; if made on a small scale it
may occasionally be of service to the watchmaker. The tool may be
=T=-shaped, one end of the horizontal portion, the copper head,
terminating in a rather thin blade, and the other enlarged, so that,
when held in the flame of a lamp, it will store up a sufficient amount
of heat. The upright part of the =T= corresponds, of course, to the
handle. After the iron has been heated just short of redness in the
dark, the end of the blade is moistened with soldering fluid and a
small piece of solder attached to it. The object to be united is gently
heated and also moistened with the fluid; the iron charged with solder
is presented to it, often with the enlarged extremity of the head
maintained in the flame of a lamp, and the solder will, as a rule, run
without again heating the object, although this might be done while the
iron is still in contact. It may be found convenient to fix the iron in
a suitable position with the lamp below the large end of the head; the
object will then be brought against the iron after being moistened with
the fluid.
=137.= It is often advisable to tin the surfaces to be united previous
to soldering them; in order to do this they are moistened with
soldering fluid, small pieces of solder are then spread over, and these
are fused by passing the hot iron over the surface; or the solder can
be spread after fusion by means of a metallic rod charged with the
liquid.
=138.= =Brazing.= This operation consists in soldering iron, steel,
brass, or copper, with an easily fusible brass, which is specially
prepared in the form of coarse dust, termed spelter solder, or cut
in thin strips of convenient shape (=129=). The method resembles, in
all essential particulars, the application of hard solders previously
referred to (=131=, etc.)
Heat is usually applied direct by the blow-pipe, borax being used as a
flux, and the precautions taken that are mentioned in article =130=:
it is necessary to avoid a greater degree of heat than would melt the
brass, since the object might in that case be fused. For fine work, it
is better to employ silver solder.
On an emergency, two pieces of steel can be united by brazing and
subsequently hardened, and we have successfully practiced this method
in such a case as the following: A small portion having been broken off
from the quarter-piece of a repeater, we dovetailed into it another
piece of steel of the required form, but a trifle too large at the
upper side. When the brass had run well into the joint, and the piece
was still at a full cherry-red heat, it was hardened, and afterwards
cleaned and tempered to a blue color. The upper surface was then
brought to shape with a good file, resting it on a wooden block against
a projection, and, after making sure that it would act correctly, the
whole was smoothed and polished. It has since worked well and does not
show signs of wear.
BRONZING.
=139.= =To bronze copper.= The following are two methods recommended
for bronzing objects of this metal, for example, a medal.
Dissolve two parts of verdigris (acetate of copper) and one part
of sal-ammoniac in vinegar. Boil the solution, skim it, and dilute
with water until it no longer possesses a feebly metallic smell, nor
produces a whitish precipitate on the addition of water. Then let it
boil again in an earthenware or porcelain vessel and transfer it, while
boiling, into another vessel containing the perfectly clean medals,
etc., and place the whole on the fire. As soon as the medals assume
the required color, remove them, and wash carefully in clean water.
The objects must not be left too long in the acid bath over the fire,
because the layer of oxide would become too thick, and would easily
scale off the surface; whereas, if the operation is properly conducted,
the coating adheres so firmly that it cannot be separated even by
scraping. Of course, it is only after a certain number of trials, and
with experience, that the exact moment can be ascertained for removing
the objects from the bath. It is very necessary that the bath be not
too concentrated, as the superficial oxide becomes proportionately less
adherent: moreover, a whitish powder is deposited on the medal, which
turns green on exposure to the air and spoils the appearance of the
bronzing.
=140.= =Chinese bronzing.= The Chinese employ the following mixture for
bronzing copper, the several constituents being powdered before being
incorporated together: 2 parts of verdigris, 2 parts of cinnabar, 5 of
sal-ammoniac, 5 of alum, and 2 parts of the beak and of the liver of
a duck. A paste having been made, with vinegar, it is spread over the
perfectly clean surface of the copper, and the whole exposed for an
instant to the fire, then allowed to cool, washed, and the operation
repeated as often as may be needed in order to obtain the desired tint.
By adding sulphate of copper to the mixture a browner shade will be
obtained, and it may be made yellower by adding borax. Copper thus
treated is said to present a beautiful appearance, and to be so
permanent that neither air nor water has any influence against it.
=141.= =To bronze brass.= Dissolve copper turnings in nitric acid until
it is completely saturated. Immerse the brass objects to be bronzed in
this solution after they have been cleaned, smoothed with water of Ayr
stone, and heated to such a temperature as the hand can just support;
on being placed over a charcoal fire they will assume a green color;
rub them over with rags, repeat the immersion and heating over charcoal
until the required tint is obtained. The shade may be improved by
oiling the finished surfaces.
It is asserted that by immersing copper articles in molten sulphur
containing lampblack in suspension, they assume the appearance of
bronze; and that they may even be polished without losing their color.
GILDING.
=142.= =Gold gilding without the aid of mercury.= Prepare the gold in
fine powder, as explained in the following paragraph, or procure it
from the dealers in chemical products, who manufacture it of various
tints. Make a mixture of this powder with pure rock salt and cream
of tartar (bitartrate of potash), pulverized in the same manner as
described in speaking of silver-plating and take the same precautions
in its application.
The gold surface will present a dull appearance; acid cannot be used to
improve its color when operating, for example, on a wheel with attached
pinion, but the same result may be attained by a very simple method.
Rub the object after plating with cream of tartar, mixed with a large
proportion of water; then immediately wash in an abundance of warm
water at not less than 40° C. (104° F.); soap it thoroughly, so as to
neutralize any acid that may remain, and finally pass through alcohol
to dissolve any remaining soap.
The surface will be still further improved by rubbing with a very hard
piece of pith, such as is occasionally met with.
M. Robert, in describing the above method, adds: “In this manner I have
gilded cocks, domes, compensation balance weights, and even their brass
rims. When, skilfully and expeditiously performed, the pinion need
not be discolored; but, if it is at any time slightly marked, it may
be restored by at once rubbing the surface with a soft stick and fine
rouge.”
=143.= =Preparation of the gold powder.= As already observed this can
be obtained of any desired color from the dealers in chemical products,
but the following method is given for the benefit of any one who
desires to prepare it for himself:
Place some gold in thin leaves in a dish, and add a little honey,
thoroughly intermixing the two by the aid of a glass rod flattened
at one end; then place the paste so obtained in a glass of water
containing a little alcohol, washing it and allowing the powder to
settle. Decant the liquid and again wash the residue, repeating the
operation until a fine brilliant powder is obtained. This powder is
mixed as required with rock salt and powdered cream of tartar in the
manner already described.
=144.= _Second method._ Dissolve one part by weight (say about ten
grains) of pure gold, rolled very thin, in aqua regia (=155=) contained
in a porcelain dish, which may be gently heated on a sand-bath, and
evaporate the acid until it assumes a blood-red color. Add about
30 parts, by weight, of warm distilled water, in which 4 parts of
crystallized cyanide of potassium have been previously dissolved;
thoroughly stir the mixture with a glass rod, and filter it through a
glass funnel.
=145.= _Third Method._ Roseleur recommends the following solution for
gilding by simple immersion. Distilled water, 17 pints; pyrophosphate
of soda (in crystals) 28 ounces; hydrocyanic acid, 1-3 ounce;
crystallized perchloride of gold, 2-3 ounce. The pyrophosphate is
added, in small quantities at a time, to 16 pints of water, in a
porcelain vessel, stirring with a glass rod and applying gentle heat;
then filter and cool. The gold salt is dissolved in a small amount of
water; filter and add to the cold solution of pyrophosphate; lastly,
add the hydrocyanic acid and the solution, heated to the boiling point,
is ready for use.
The articles to be dipped must be thoroughly cleansed and passed
through a very dilute solution of nitrate of binoxide of mercury; they
must be constantly agitated while in the bath and the best coating is
obtained by dipping the articles in a nearly exhausted solution of the
same kind immediately after the mercury solution.
=146.= =Electro Gilding.= But the method most usually adopted is that
in which a battery is employed. It is, however, impossible, within the
limits of this work, to explain the precautions that are necessary in
conducting the process, managing the battery, etc., and the reader must
be referred to works on electro-metallurgy for these details.
=147.= =To prepare the pieces to be plated.= After the surface has been
stoned, boil the object a few minutes in a solution of soda or potash,
and rinse in clean water.
Roseleur, in the articles already referred to, gives very full
instructions, of which the following is an outline. The reader who
desires to obtain more complete information can consult his works.
Attach the pieces to a cork and brush with a clean brush charged with
water and pumice-stone powder and thoroughly rinse. Place them in a
solution consisting of: water, 2¼ gal.; nitrate of binoxide of mercury,
1-14 oz.; sulphuric acid 1-7 oz. Then rinse again.
=148.= =Graining.= Mix thoroughly with the application of moderate
heat, silver powder, 1 ounce; pure common salt, finely powdered, 13
ounces; cream of tartar 4 to 5 ounces. Make a thin paste of this
mixture with water and spread with a spatula on the pieces; having
mounted them on a cork to which a rotary motion is given, rub them
in all directions with a brush with close bristles, adding fresh
paste from time to time. When the desired grain is obtained, wash and
scratch-brush with revolving wire brushes. Three of these are often
used of varying degrees of hardness and a decoction of liqorice, weak
size or stale beer is liberally applied to the surface.
=149.= =Resist.= This is a composition for covering steel parts in
order to protect them from the action of the acids, etc., in the
various processes of cleaning, graining and gilding. It consists
of yellow wax, 2 ounces; clear resin, 3⅓ ounces; very fine red
sealing-wax, 1½ ounces; finest rouge, 1 ounce; Melt the resin and
sealing-wax in a porcelain dish, then add the yellow wax, and when the
whole is thoroughly liquid, gradually add the rouge, stirring with a
glass rod. The parts to be coated are slightly heated and covered with
the mixture.
To remove the resist after the gilding process is completed, place the
pieces in warm oil or turpentine, then in a very hot soapy or alkaline
solution and lastly in fresh water.
=150.= When prepared as above explained, the object may be gilt by one
of the preceding methods; of course a hot solution cannot be resorted
to when the resist has been applied.
=151.= =To clean objects that are of gold or gilt.= The following
method is equally applicable to pieces that are gilt, such as cocks,
domes, etc., the frames and parts of timepieces and to either gold or
gilt jewelry.
To about a tumbler of water add 20 drops of strong ammonia. Immerse the
object several times in this mixture and brush it with a soft brush; as
soon as the operation appears to be completed (which experience will
soon enable the workman to ascertain), wash in pure water, then in
alcohol, and dry with a fine linen rag. The original brilliancy of the
gilding will then be restored.
When the coating is thin and has been galvanically deposited, only very
soft brushes must be used.
Gilders, instead of dipping in alcohol and drying with a linen rag,
usually immerse the pieces in boxwood sawdust, leaving them long enough
to become thoroughly dry; after this treatment they merely require to
be shaken and lightly rubbed with a fine brush.
The sawdust must be perfectly dry; indeed it is a good plan to slightly
warm it by placing the wooden box containing it for a few minutes on a
hot oven or stove in the winter and exposing it to a hot sun in summer.
Instead of ammonia, alum (=156=) is sometimes boiled in water and
the objects dipped two or three times in this solution, subsequently
brushing as in the previous case.
=152.= _To restore the dead surface of gold or gilt objects._ Place
them for two or three minutes in chlorine water, rinse them in clean
water, soap them and finally dry in sawdust. It is advisable that parts
that are polished be prevented from actual contact with the liquid as
it would produce a somewhat deadened surface.
=153.= _To clean gold jewelry after soldering._ Particles of binding
wire are often left adhering to the surface of jewelry after soldering,
and, on dipping the object into the dipping liquid, a layer of oxide
may be formed. This can be removed without detriment to the polished
surface by plunging the object for a few seconds in nitric acid
(=155=).
ACIDS AND SALTS.
=154.= The watchmaker has occasion to employ a few acids and salts. He
should never forget the advice already given to keep them away from his
work-bench and always to well wash a piece of metal that has been in
contact with them.
=155.= =Acids.= _Nitric Acid_, either in a concentrated or dilute form,
will dissolve iron, steel, copper, lead, silver, zinc, brass, nickel,
mercury, German silver. It does not dissolve tin, but reduces it to a
white powder, known as metastannic acid. Hence, if an attempt be made
to dissolve bronze which contains tin, this metal is deposited, and the
copper and zinc pass into solution.
_Sulphuric acid_ will dissolve iron, steel, copper, tin, silver, zinc,
brass, nickel, mercury, German silver.
_Hydrochloric acid_ will dissolve iron, steel, zinc and nickel and has
a slow action on copper, tin, brass and German silver.
_Aqua regia_, a mixture of about 2 parts hydrochloric and 1 part nitric
acid, will dissolve all the above-named metals, and in addition, gold
and platinum, although separately neither acid will attack these metals.
_Hydrofluoric acid_ attacks and dissolves all metals, except platinum,
lead and silver with violent effervescence. It is also used for etching
on glass or enamel. It is usually preserved in gutta-percha bottles,
and is of such a dangerous nature that no use should be made of it
without a good knowledge of its properties.
Acids are rarely employed pure by watchmakers; they are diluted with
water. Nitric acid of commerce has a density of about 1.4 (38° on
Baume’s hydrometer). If this density is reduced by the addition of
water to 1.16 (20° Baume), we obtain the acid most commonly employed.
For cleaning metallic surfaces prior to soldering etc.; for giving
a grained surface to brass, and for whitening blue steel, special
proportions are found most convenient, which the reader can best
determine experimentally for himself, remembering that the action of
the acid should neither be too quick nor too slow. When once he has
ascertained the best proportion, he can always recover it by the aid of
the hydrometer.
=156.= =Salts.= _Borax_ serves as a flux in soldering gold, silver,
platinum, etc., (=131=); also for the same purpose in brazing (=138=);
it is met with in crystals or as a powder.
_Sal-Ammoniac_ (also called _Chloride of ammonium_), is used for
soldering tin, either as a powder or made into a paste, with sweet oil
or with water, or mixed with resin.
_Alum_ dissolved in water may occasionally be used in place of nitric
acid for cleaning surfaces that have been soldered; it attacks iron
or steel more energetically than copper, zinc, or brass. This fact is
often taken advantage of for removing broken screws, etc., from brass
plates. All other steel parts are removed and the plate placed in a
solution of alum, when the steel screw is gradually eaten away by being
converted into rust.
In 100 parts of cold water, only 9 parts of alum will dissolve, but if
the water be boiled, it will take up 75 parts. Its action will then be
proportionately more energetic when boiling.
OIL.
=157.= The oil intended for use as a lubricant for watchwork,
etc., should be kept away from the light, as otherwise it would be
discolored; it is on this account that the bottles containing such oil
are frequently covered with black paper. Only the quantity wanted for
immediate use should be placed in the oil-cup.
Two preliminary tests will afford some indication as to the quality of
an oil. A thick layer is placed on a small portion of the surface of a
glass plate, and side by side, a similar layer of another oil used for
comparison, and they are exposed to the air for some time without being
touched. The one that is found to be sticky under the finger when the
other has dried up will, in all probability, be preferable. The second
preliminary test is made on a whetstone; it is usually found that the
oil that takes the longest time to thicken is of better quality. Of
course these tests will only suffice to afford a rough approximation,
and cannot be accepted as conclusive.
The mode adopted for testing either the acidity or the purity of oil
will afford no evidence as to how long it will maintain its fluidity;
and very good results have at times been secured by the use of oils
that were slightly acid, or from mixtures of oils of two or more
qualities.
Many of the methods recommended for purifying oils are to a great
extent illusory, for they cannot impart to the fluid characteristics
that are wanting from the beginning. Success depends largely on the
skill of the manipulator; and if he is not endowed with the power of
judging, mainly by the taste, whether oil satisfies certain prescribed
conditions, he can never be certain of the result. Crops differ as
regards degree of maturity, etc., from year to year; and the animals
from which oils are procured are rarely in the same condition as
regards health, age, nourishment, etc.
Tests made on a whetstone, and on a window-pane, as well as
observations made on drops of oil placed in jewel holes, or in oil-cups
in a metal plate kept for the purpose—some of the drops being exposed
to the air, while others are in closed boxes—will afford valuable
indications; and according to the observations of M. H. Robert, it
is safe to consider an oil bad if, at the end of six or eight days
after being placed on a plate of good brass, it shows a marked green
tinge—especially so if a clearly defined fringe forms round the drop,
or else if the brass itself is discolored.
After all, the only evidence on which the watchmaker can rely is that
which he obtains by experimenting on watches which he keeps to lend to
his customers while their own are undergoing repair, and these trials
should last for at least a year.
And there is great variety among the wearers of watches. Some live in
constantly varying temperatures, often dusty; many ladies use perfumes;
some persons perspire more than others; all these causes influence the
oil, and make it alter or evaporate more rapidly in one watch than in
another.
=158.= =To secure the maximum permanency in oil.= In the case of very
many watchmakers who complain bitterly of the oils they employ, the
fault is their own and not that of the oil; for they neglect the most
simple precautions, both in purchasing and in using it.
The following are a few points to which attention should be given:
Do not buy, from motives of economy, bottles that have lain for years
in the shop.
Keep the oil away from the light, and only take in the oil cup the
amount required for immediate use, as stated above.
Ascertain that the watch-cases close well. If they do not, there will
be air currents generated, and the oil will suffer.
The oil in a cylinder escapement will always deteriorate very rapidly;
some watchmakers coat over the inside of the dome-joint and recommend
the owner not to open it. By doing so, the oil can be maintained in
good condition at the escapement for a long time.
Lastly, when cleaning a watch, the work should be conscientiously done.
This point is very important.
When the parts are carelessly cleaned with soap, or with impure
benzine, they will, after a few months, assume a dull colour, in
consequence of a thin layer of the materials used in cleaning having
been left on the surface. It has at times been noticed that steel work
was preserved from rust through the perspiration of the wearer, after
being cleaned by certain fluids. Evidently this was due to a thin
coating having been left on the surface of the metal. The conclusion to
be drawn is obvious: clean carefully; push the pivots into rather hard
pith; finish with a soft brush in proper condition, and clear out all
pivot-holes with pegwood.
=159.= =Mixed oils: camphorated oils.= Good results are frequently
obtained by mixing together two different kinds of oil. Thus, American
watch oil, which is very fluid and apt to evaporate at the temperature
of the pocket, is improved by the addition of a somewhat thicker oil. A
mixture of real American oil with the Rodanet oil has been recommended
as excellent.
There are some who advocate the addition of a small quantity of camphor
to an oil that is known to be satisfactory, but we cannot answer for it
from personal experience.
=160.= =Sinks.= In cleaning, it is important to avoid removing the
gilding in the oil sinks of watches, or the superficial oxide in the
sinks of clocks that have been going for a considerable time. For if
it be removed, there will be a fresh coating formed in time, and this,
too, at the expense of the oil.
In new timepieces that are not gilt, it is well worth while polishing
the sinks over their entire surface. If not applied too liberally, the
oil will then be more likely to remain in contact with the end of the
pivot. Moreover, as the surface is smoothed and hardened, and its pores
are, as it were, closed by the action of the polisher, the oil will
oxidize more slowly. This fact was first pointed out by Robin.
=161.= _Caution to be observed in applying oil._ The precautions to be
observed in applying oil will be better considered in Part V. of this
work, where we shall describe the method of cleaning and putting a
watch together.
=162.= =Retention of oil on acting surfaces.= Since oil is essential
in order to diminish friction, and the movement of the bodies to
which it is applied tends to drive it from the surfaces of contact,
it is important, with a view to its being constantly brought back and
maintained in proximity to these surfaces, that they be formed in
accordance with certain rules based on the laws of hydrostatics.
ALCOHOL.
=163.= Only what is known as rectified alcohol should be used in
cleaning parts of watch work. The copper pan in which it is made to
boil should not be too thin. The handle should be so arranged that it
can be fixed in the vise, and the lamp held under the pan.
When, in heating, the alcohol ignites, it is best not to attempt its
extinction by blowing; if the pan is held against the under side of
the bench, the flame will at once be put out, or this can be effected
by merely laying a piece of sheet metal over the pan. A good plan for
preventing ignition is to make a lid of wire gauze, which is placed
over the pan during the application of heat.
The substance known as “methylated spirit” is a cheap preparation
of alcohol, and of use for burning in a spirit lamp, and for other
purposes where the alcohol is not required to be pure.
BENZINE, ETC.
=164.= This and other preparations of a similar nature, such as Essence
Lemoine, Essence Genevoise, etc., are much used for dissolving clogged
oil and other substances of a greasy nature from parts of watches in
cleaning.
POLISHING MATERIALS.
=165.= The following account of the materials used for polishing, is,
for the most part, extracted from Holtzapffel’s _Turning and Mechanical
Manipulation_, to which the reader is referred for fuller information
in regard to them, and to their mode of application:
=Buff Leather= glued to a flat surface, or to the edge of a revolving
disc, is used with emery, crocus, rottenstone and other powders.
=Charcoal= is much used by steel and copper-plate engravers. That made
by burning elder without access of air is considered the best, but
willow and elm have also been recommended.
=Diamond=, in the form of powder, is used by lapidaries, seal
engravers, and watch jewel makers. The latter obtain the diamond
_bort_ that is rubbed off stones in faceting, and they separate it
into various degrees of fineness, by decantation (=168=). The mode of
applying it is described in articles =207=, =216=.
=Diamantine=, Sapphirine, Rubitine, etc., are names given to various
chemical preparations for polishing, to be obtained at the tool shops;
they must not be assumed to consist in any way of the jewels from which
their names are derived.
=Emery.= At the present day, oilstone dust is very frequently replaced
by emery with oil or water, especially in clockwork. Any required
degree of fineness can be obtained by decantation. Emery dust is
sometimes used in place of rouge for polishing.
The solid emery wheels and sticks, that are now common in the trade,
work rapidly, but they have the disadvantage of heating steel, and
many of them soon become pasty. The heating renders them less suitable
for grinding gravers, but they are very convenient for roughly shaping
steel work, or removing the hard surface caused by the application of
heat.
_To make emery paper._ If occasion requires it, this can be done as
follows: Fix a sheet of stout rope manila paper on a board, glueing
it round the edge. Having put emery powder into a sifter, the mesh of
which has the requisite degree of fineness, and rapidly covered the
surface of the paper with thin hot glue, shake the sifter lightly over
the paper until it is evenly covered, and leave to cool. When dry,
detach the paper and shake it vigorously to detach loose grains. Cloth
may be used instead of paper, if desired.
=Hone slates.= Under this heading are included a great variety of
stones used for smoothing and polishing.
_Ayr stone, or water of Ayr stone_, is much used for smoothing brass
work prior to gilding (=142=), etc. It should be kept wet in order to
prevent it from becoming hard.
_Blue polishing stone_ is much used by jewelers, clockmakers, and
others; it is recommended for use in spotting (=174=) and for polishing
wheels (=176=.)
_Oilstone._ This forms the quickest cutting whetstone known. Oilstone
slips are used by watchmakers after the manner of files. Oilstone
powder, or dust, is much used in the earlier stages of polishing, and
is preferable to emery in that it does not leave particles embedded in
the surface of the metal. On pewter laps it may also be employed for
polishing steel work.
_Oxides of iron._ Under this head are included the several materials
known as crocus, rouge, red-stuff, colcothar of vitriol, etc. It
is advisable to remove gritty particles from these materials by
decantation (=168=) before using.
_Pumice-Stone_ is extensively used for polishing cut glass, and is
applicable to brass and other metal work.
_Putty Powder_ is oxide of tin, or, more commonly, of tin and lead
in varying proportions. The whitest kind, provided it be heavy, is
considered the best.
_Rottenstone._ This variety of tripoli is of the greatest value for
polishing brass work, as well as for silver, glass, and even the
hardest stones.
_Tripoli_ is of a greyish yellow or red color, and consists mainly of
silica. Its principal use is in the polishing of hard woods.
_Whiting_ is common chalk, ground, washed to remove sand, etc., and
dried in lumps.
=166.= =Polishing Stones.= The following method is described by M.
Cadot for preparing these stones, which are very useful for polishing a
wheel that is not riveted to its pinion (see article =185=).
Carefully select a blue stone; after dressing its surface, smooth it
with emery paper of gradually increasing fineness. Saturate the surface
with oil, and rub it with a common piece of rough sapphire, one face of
which is flat and partly smoothed, until the surface of the stone is
hardened.
Such a stone is used dry. The wheels must previously have been
carefully smoothed, since the stone does not abrade the metal. If care
is taken to avoid scratches, the surface will last for a long time,
although, of course, it is only serviceable for gold, brass, nickel or
metals of a similar degree of hardness.
=167.= The several materials used for polishing must be kept carefully
packed (glass stoppered bottles are preferable), as a few grains of
dust, or of foreign bodies, will suffice to prevent the operation of
polishing from being successful. Polishers should be filed very smooth,
with a perfectly clean file that is not quite new. Files that are dirty
or new will deposit small hard particles of dirt, or cause pieces off
the points of their teeth to become embedded in the surface of the
polisher.
PREPARATION OF POLISHING MATERIALS.
=168.= =Decantation.= This consists in causing a material in a fine
state of sub-division to fall slowly through a liquid with the view to
separate coarse particles, or various degrees of fineness, by taking
advantage of their different rates of descent.
The watchmaker should prepare all his smoothing and polishing
materials, etc., by decantation. He will by this means obtain them in
grains that are much more uniform in size, of any required degree of
fineness and free from hard or large particles.
[Illustration: _Fig. 40._]
The operation is exceedingly simple. The material having been pounded
under the hammer or otherwise, is thrown into a vessel more or less
filled with a liquid, water, oil, etc. After being thoroughly stirred,
it is allowed to partially settle, and the liquid is carefully poured
into another vessel. All the coarse heavy grains will be found as a
residue in the first vessel; they are collected and used for coarse
work. After again stirring and leaving to settle for a longer period,
the liquid is again poured off, and the powder thus separated will
be the second degree of fineness, so that it may be termed No. 2. By
successive operations, in which a gradually increasing interval of time
is allowed, Nos. 3, 4, etc., can be obtained; that is to say, a series
of powders of the same material but presenting a greater degree of
uniformity in the size of grains and of gradually increasing fineness.
It may be observed that when the powder of the requisite degree of
fineness is nearly attained the mass should be left to settle until
the following day, or, rather, until the fluid is clear; then decant
carefully so as not to lose any of the deposit.
When treating a material that is soft and friable, it should be crushed
between the fingers, as by using a hammer hard grains of foreign
matter might be accidentally intermixed. Oil may be used for decanting
diamond powder or oilstone dust for smoothing; water for rottenstone or
tripoli; alcohol for hartshorn, etc.
=169.= =To prepare diamond powder.= Select rough diamonds of a blackish
tint, of such a size that there are four or five to a caret. These are
crushed in a hard steel mortar of the form indicated in fig. 40, the
pestle being provided with a small stuffing box that can be brought
down on to the mortar to prevent the escape of diamond-dust; but it is
well to first crush one stone, with a single blow of the hammer on the
pestle; remove all the fragments and examine the end of the pestle;
it will be found that a number of particles have bedded themselves in
it; these should be examined to select pieces to serve as drills and
gravers. The larger fragments serve for gravers, and particles should
be sought that are as nearly as possibly triangular prisms about
¹⁄₅₀ inch long for making drills. The other stones may be treated in
similar manner till enough fragments are found. Now place all other
pieces in the mortar, and continue for two or three hours striking the
pestle with the hammer, turning it partly round after each few blows
to prevent the powder from imbedding itself in the steel. When no
“bite” is perceived in rotating the pestle, the diamond is sufficiently
reduced; it is shaken out of the mortar into a watch-glass containing
the most limpid oil attainable, and if necessary the fragments are
released by a steel spatula, at the same time striking the external
surface of the mortar with the hammer. Thoroughly mix the oil and the
powder, subdividing the latter as much as possible by rubbing against
the glass with a spatula; allow the mixture to rest for an hour and
pour off the liquid into a second glass, leaving the larger particles
behind. Leave the oil in the second glass for four hours; then decant,
into a third glass with the same precautions; this is left for eight
hours; the next glass sixteen hours. When all the powder has settled
pour off the oil, and the several degrees are ready for use.
Some jewelers prefer to leave the powder for two or three days in
a mixture of equal nitric and sulphuric acid in order to dissolve
particles of steel. The acids are then much diluted with water, left
for some days and decanted. Then wash the powder in two fluid ounces of
pure alcohol, leave for two days, decant and dry, and afterwards treat
with oil. The operation is long and hardly necessary.
SMOOTHING.
=170.= If a surface is smoothed well, the labor of polishing will be
diminished by at least one-half, and it is an essential preliminary if
a good gilding on brass is required.
The materials most frequently used are emery and oilstone dust for
steel, pumice and water of Ayr stone for brass. The stones should not
be traversed by veins, nor exhibit hard grains. Powders should be
freed from large or hard grains by decantation, and it is advisable to
repeat this operation several times in order to have several degrees of
fineness.
SMOOTHING OF BRASS.
=171.= Every watchmaker knows that after finishing the object with a
smooth file, it is smoothed, first with a blue stone or rather coarse
water of Ayr stone, and then with one of finer grain. If the brass
is to be gilt, the operation is concluded with a series of circular
strokes, so as not to leave any striæ or bright spots; if the surface
is to be _spotted_ or watered the final strokes should all be parallel.
A soft piece of charcoal applied with water may also be used on objects
intended for gilding; in other cases it is used with oil.
=172.= =Wavy or watered smoothing.= This is done with water of Ayr
stone and oil carefully prepared, or with a piece of wood charged
with oilstone dust, etc. The oiled corner of an emery buffstick can
occasionally be used.
To obtain wavy undulations on a smooth piece of metal, the finger
should first be placed at the point of commencement of the undulations.
Resting the wood or stone against the finger, it is moved a little in
a straight line, and then in a series of semicircular waved lines,
from right to left or left to right. The finger is advanced through a
definite distance and the operation repeated, and so on.
A very good watered surface can be produced with soft charcoal. With a
view to increasing the regularity in the marks, a rule may be laid on
the object, against which the charcoal is brought.
[Illustration: _Fig. 41._]
Parallel watering is usually done mechanically, but any watchmaker can
secure regularity by the following simple device.
Fix a graduated rule _t g_ across the cork (fig. 41) and two pins A A,
to form stops for preventing the stick or stone from traveling too far.
A division of the rule is made to correspond with the line _v v_; and,
when the first line has been traced, advance the object by one, two or
three graduations of _t g_, according to the interval that is to be
left between successive undulations. Then trace the second wave, and so
on.
=173.= =Wavy and curvilinear smoothing.= These are of two kinds; some
are entire circles, which we shall proceed to consider; others radiate
in curves from the circumference to some other point of the circle
as, for example, many of those that are met with on keyless ratchet
wheels. The latter will be discussed farther on, when discussing the
smoothing of steel, for the process is identical for both steel and
brass, except that with the latter named metal and nickel the stick may
be replaced by a strip of zinc or tin, and coarse rouge is used.
=174.= =Circular snailing or spotting.= This is produced on a special
tool by which several motions can be given to the object, but
watchmakers, as a rule, so seldom have occasion to trace this class of
ornament, that it will suffice to explain how it can be produced by the
appliances that everyone has at hand.
The universal mandrel may be employed for the purpose, but, in that
case, the operation is a very slow one, whereas, with the ordinary
lathe, it can be done both rapidly and well.
[Illustration: _Fig. 42._]
Adjust a rest of the form shown at s (fig. 42), taking care that the
height of the center is sufficient; the small rectangular bed _a a_ has
a projecting edge, divided by equidistant graduations. To the headstock
of the lathe is attached, at _b_, a piece of bluestone or wood. Having
set the rest at a convenient height, and holding the object to be
spotted, P, on the rest, bring in it contact with _b_ when in rotation.
When the mark is made, lean the object from _b_, slide it along _a a_
so that its edge coincides with the next division and make another
mark, and so on until an entire row is completed. Then raise or lower
the rest and repeat the process for a second row, and so on.
Instead of applying oil to the acting face of _b_, which would have to
be renewed at each operation, it is usual to cover the object P with
oil, if _b_ is a stone, or with oil mixed with the substance used for
smoothing, if _b_ is of wood. If this precaution is taken, the work
will progress much more rapidly.
When the object operated upon is of irregular shape it must first be
attached to a rectangular plate and then proceed as already stated.
A still more simple method, but one that is, in certain cases quite
sufficient, consists in passing through the poppet-head a center of the
form _f d_ (H, fig. 42) which is caused to rotate by the fingers or any
other means.
[Illustration: _Fig. 43._]
To make spottings that, instead of being parallel, radiate from the
center to the circumference, the rest _a a_ must carry a disc that can
rotate on a clamping screw, and is maintained in position by a finger,
with an even number of equidistant divisions on the circumference of
the disc. The object to be operated upon is then fixed to the disc, and
a stick used, the diameter of which is equal to the distance between
two radii that pass through a pair of graduations on the disc; for
example, the small circle _s_ (fig. 43). A series of circular spots is
then made by gradually rotating the disc. Now replace the rod _s_ by
one of the diameter _n_; advance the support until it corresponds with
the position _n_, and make the second range of circular spots, and so
on. The figure renders any further explanation unnecessary.
The watchmaker who has clearly followed what precedes will be able,
should occasion require it, to construct a special tool acting with
certainty; but it will be well to remember that there is a great
advantage in driving the spotting stick by the foot, and bringing it
down on the object by a small hand lever, after the manner of the
drilling machines used in factories.
SMOOTHING OF STEEL.
=175.= The smoothing of a steel object is commonly done on a piece of
cork, with a large iron polisher charged with oilstone dust and oil. If
a flat surface, it can be finished with a copper polisher or on a sheet
of glass. In the case of staffs, arbors, etc., that are not intended
to be polished subsequently, a certain degree of brilliancy is given
to the surface by rubbing with wood, usually pegwood, or with a stick
covered with the finest emery paper and oil.
A surface that will not be subjected to friction—as, for example, the
head of a screw—can be smoothed rapidly and well with a dry emery
buffstick if little metal has to be removed, and the polishing can then
be at once proceeded with. Only one cleaning is in this case necessary,
for after the emery it will suffice to rub with pith and pass a brush
over the surface.
For ordinary work, smoothing a staff or head of a screw with dry, fine
emery and finishing by the friction of rather hard pith backwards and
forwards, will give a fairly satisfactory surface.
=176.= =White and dead smoothing.= To produce a graining, the piece of
steel must be previously smoothed in the ordinary way, perfectly flat
and free from scratches. The graining is produced by rubbing the object
on a sheet of ground glass with the finger, taking very small circular
strokes, especially towards the end of the operation. The degree of
success depends on the quality of the oilstone dust employed. It must
be very fine, and it will be a prudent precaution to decant the powder
in water, or preferably in oil, and not to use the earlier deposits
(=168=).
When the oilstone dust is not very good, it may be washed in
hydrochloric acid, which dissolves most of the hard grains, but it will
require to be thoroughly washed in water afterwards, on account of the
difficulty there is in removing the last traces of the acid. Of course
such a method is only to be resorted to on an emergency.
Perhaps the most difficult piece to grain is a keyless barrel ratchet,
because if the operation is at all prolonged the edge of the ratchet
may become white before the center and it may even polish. If this
happens, the ratchet should be held in the hand and rubbed with a piece
of pith cut to a blunt point with a flat end. By this means it is easy
to act on the center, avoiding the edges.
=177.= =Dead white or frosted surface.= After having grained the steel
in the manner above indicated, if it is required to obtain a dead white
frosted surface, employ a mud formed of Arkansas stone dust, or the
sticky deposit on a whetstone, which is more easily obtained. It should
not be too yellow, as the result is all the better according as a
greater number of steel particles are mixed with the oil; at least, so
we are informed by some very good workmen. A large piece of elder-pith
having been divided into two equal parts lengthwise, is smoothed with a
new, clean file; the mud is spread upon it, and the piece of steel is
moved over it with circular strokes as in producing the graining. In
this case the movement can be rapid. If the operation be well done, and
if the oilstone dust used be of good quality, the object will, after
being cleaned, present a beautiful uniform white surface in which the
graining is still visible. Experience and knack are everything in the
proper conduct of such an operation, especially in its concluding stage.
The surface may be cleaned in pure benzine mixed with a little
sulphuric acid, followed by a very clean buffstick, which will impart a
brilliancy to the metal.
M. Bean recommends fine Turkey oilstone powder mixed with turpentine
as the best preparation for rapidly producing a dead smooth surface on
steel work.
Workmen that are constantly engaged in graining employ a foot-wheel for
the purpose. The ground glass is fixed so that, although not rotating,
a small circular motion is communicated to it. The steel is then simply
held against it; indeed, several pieces can be grained in this manner
at once.
To the methods above described we would add the following, which is
successfully practiced by several English workmen:
They lightly fix the ratchet, for example, by its edge, and finish the
smoothing with a piece of pith, more or less charged with pure charcoal
powder and fine oilstone dust. Here also knack is mainly instrumental
in insuring success.
=178.= =Snailing.= To produce the snailing on a fusee or on keyless
wheel-work, the device shown in fig. 44 can be used. The ratchet or
fusee is mounted between one pair of centers and driven by a cord
from a foot or hand-wheel. The copper or iron lap, having a diameter
equal to about three times that of the surface to be snailed, is
charged with fine emery powder and oil, or oilstone dust, etc., and
set in contact with the face of the steel, which thus causes it also
to rotate. The direction of the snailing will be the same, whether
the rotation is to the right or left. If it be required to change the
direction, the relative positions of the two pieces must be reversed.
It has been already observed that brass and nickel can be snailed in
the same way, employing a zinc or tin lap and coarse rouge (=173=). In
some cases, hard wood laps can be used for these softer metals.
In keyless steel wheels a beautiful snailing can be obtained with
Arkansas stone mud (or, in its absence, the greasy mass from an
oilstone) mixed with polishing rouge.
[Illustration: _Fig. 44._]
With reference to the little tool shown in fig. 44, it may be observed
that, if the axes of both the steel piece and lap were driven by bow or
otherwise, the surface would be polished and not snailed.
In the absence of the tool here referred to, any one can easily
construct one for the purpose which will adapt to the mandril or a
foot-lathe: in order to help him in doing so we will describe one
designed by M. Cadot, of Paris.
=179.= _Tool for snailing._ This is shown in fig. 45, and we would at
the outset observe that it can be used equally well for polishing. To a
shoulder at the extremity, A, of a piece of steel rod, B (which takes
the place of the slide-rest cutter) is riveted an L-shaped piece _c
c d_, and to the point _d_ is firmly fixed by a screw or rivet, the
upright piece _d h_ parallel to _c c_; this piece is enlarged at _h_ so
as to give a bearing to a hardened steel screw, with a hollow point, in
the axis of B: the lap is supported between this screw and a hole in
the center of A. The figure will suffice to indicate the form of this
lap which is dished internally as shown by the dotted line. It is made
of iron or copper if intended for use with hardened steel.
[Illustration: _Fig. 45._]
The piece to be snailed is fixed to a chuck of the foot-lathe, and,
having fixed the rod B in place of the cutter, the lap is brought, by
means of the slide-rest screws, in contact with the steel, taking care
not to set it up to the center, as snailing that starts from the center
is not so good. Having charged the lap with fine emery and oil, the
object is rotated and it sets the lap also in motion.
It was mentioned above that this tool can be employed for polishing:
for such a purpose use fine rouge, replace the lap by one of bronze or
bell-metal, fix a ferrule at _i_, and, while the object turns in the
lathe, rotate the lap with a bow.
By fixing a rod at L instead of at B, the tool is at once adapted to be
used in an ordinary pair of turns, as it can be fixed in place of the
T-rest; but it is not so easy to secure parallelism of the two surfaces.
=180.= =To restore the watered surface in nickel movements, etc.=
Although the following is employed for nickel (or rather German silver)
it may be well to observe that it is equally applicable to all other
metals.
As these nickel movements are not gilt subsequent to being repaired,
it frequently happens that the water marks on the surfaces do not
correspond. By the aid of the following device watchmakers can correct
this fault, but we must warn them that, as in all operations involving
dexterity, they must first make experiments in order to acquire the
requisite manual skill.
[Illustration: _Fig. 46._]
On a small open frame C C, fig. 46, fix several parallel bars _f l_,
_e d_, etc., and on two of these adjust a slide _p o n m_, with two
strips glued underneath so that it can travel up and down between _a_
and _b_. On _p o n m_, fix a guide of convenient form, as G; and, after
cementing the piece, say A, that is to be watered on a board resting
on the bench, place the frame C C above it and trace the figure of the
guide with a pegwood stick charged with polishing material. The same
figure can be reproduced in parallel rows as the guide can be moved up
or down.
By varying the shape and position of the guides, the water lines can
take the form of waves, festoons, circles or ovals. In the two latter
cases the guide has apertures of the requisite form, and the board that
carries A, not being more than half the size of the aperture, can be
moved about by hand or by a tool.
If preferred, one of the bars, as _e d_, can be graduated and
arrangements can be made for clamping the slide by screws in any
position.
These explanations will suffice to enable any intelligent watchmaker,
after a few trials, to imitate successfully any of the beautiful
watered surfaces that are, on a manufacturing scale, produced by
machinery.
As regards the material to be used, first mix medium rouge and putty
powder in equal proportions. It will be possible to decide from the
shade obtained whether more putty powder should be added, because when
there is too much rouge, the surface does not acquire a good white
color.
POLISHING.
=181.= =To polish brass.= When it is required that a surface be
maintained perfectly flat, first dress with somewhat coarse water of
Ayr with blue stone and then go over with a softer stone. Next work
with fine rottenstone and oil on a felt or buffstick for objects of
large dimensions and on a piece of pegwood for smaller articles. They
are then soaped, washed and dried in sawdust (=151=).
The work can be accomplished more rapidly, but without maintaining
a perfectly flat surface, by first employing pumice-stone and oil
spread over a large piece of soft wood or felt. It is then cleaned and
polished with rottenstone.
When the form permits of it, a tin disc charged with tripoli and
rotating in a lathe can be employed.
_Observations._ Pumice-stone is powdered fine and then sifted. In using
rottenstone a piece an inch or two cube is crushed between the fingers
into a cup of water, and this is decanted so as to give several degrees
of fineness (=168=). The polishing can best be effected by using old
wood from which the sap has dried up: French chalk has but little
action if the polisher with which it is applied is from the animal
kingdom, horn for example, etc.
=182.= =To polish watch wheels.= Although the operation of polishing is
extremely simple, it is very important that a certain degree of manual
skill be acquired by practice, as otherwise the work is never of the
best.
We will here enumerate several methods of procedure, in order that,
after trial, each can select the method with which he finds himself
most successful.
_Smoothing._ The smoothing should be done carefully with very soft
water of Ayr stone, free from veins and hard grains and perfectly
flat. The wheel must then be well cleaned.
_Polishing._ In polishing, rods of walnut or boxwood, of tin, bronze or
zinc are used. A buffstick and burnisher are also employed.
The materials applicable are rottenstone (with oil or alcohol, being
made very thin in the latter case) tripoli, prepared chalk, polishing
rouge, crocus, etc. These materials have been sufficiently described in
articles =165-7.= Workmen sometimes prefer to make mixtures of two or
more substances, but it is more usual to employ them separately.
=183.= _First Method._ After smoothing and cleaning the wheel, it is
polished while resting on a piece of cork, where it is held between
the fingers which cause it to rotate; the best rottenstone is used
and is applied by smooth pieces of boxwood, about 8 inches long,
which are filed to a bevel edge. It is best to have the grain of the
wood crosswise and the polishers should be of sufficient thickness to
prevent their bending when in use.
The rottenstone can be replaced by tripoli and the boxwood by walnut.
Some wheel polishers prefer a triangular stick of pure tin or zinc
which is often planed to ensure perfect flatness; rouge, rottenstone or
tripoli can be used with it.
The wheel, after being well washed in soap and hot water, is thoroughly
dried and finished with a fine buffstick in good condition, while it
rests on a cork covered with smooth felt; this operation is with a view
to prepare the surface prior to using the burnisher.
Some polishers, instead of the dry buffstick, prefer one charged with a
little rouge, tripoli or rottenstone moistened. But such preparations
must be applied very sparingly as they involve a risk of rounding the
edges.
The burnisher is next rapidly passed over the surface of the wheel,
which rests on cork, covered with a linen rag, or on a piece of wood,
covered with smooth paper. Some give long backward and forward strokes
with the tool; others give semicircular movements. It will be found
sufficient to give short strokes from half an inch to an inch in
length. A slight motion of the wrist is all that is required and after
a few trials the necessary skill will be attained. We cannot say more.
Practice must also be relied on for determining the most suitable
pressure.
The burnisher, about half an inch wide and four inches long, is curved
in the direction of its length. A straight burnisher might be used,
but it is less safe; the angle of the burnisher set against the pinion
should be rounded off.
The burnisher is cleaned and restored by drawing across a large flat
piece of walnut charged with rouge of very good quality and very pure.
After being washed, a little white wax is passed over it, and then
it is again rubbed vigorously with a piece of cloth or a buffstick;
finally with a soft linen rag. When a tendency to stick shows itself
this operation must be repeated.
=184.= _Second process._ By this method the surfaces are somewhat
rounded off at the edges. But, although not so pleasing to the
eye, this circumstance involves no inconvenience except that, when
burnishing, the burnisher would not at once come in contact with the
entire surface; we need not, however, employ the burnisher.
Laying the wheel on a cork, some workmen smooth the wheel by covering
it with oil and fine tripoli and rubbing with a walnut-wood stick.
Others spread a layer of such a mixture first on the stick and then
rub the wheel. When no more lines are observable across the surface of
the wheel it is cleaned, placed on a fresh cork that is covered with
a soft linen rag, and polished with a fresh buff stick (or one that
has already been used for a similar purpose) and an abundant supply
of rouge or even fine rottenstone and oil may be used. The buffstick
receives a semicircular movement in all directions in order not to
needlessly round the corners, the edges of the teeth and the crossings.
It is then washed in warm water, bathed in alcohol and dried with a
fine linen rag.
=185.= _Third process._ After smoothing with a very soft stone, rub it
with a piece of the root of boxwood cut across the fibre, on which is a
layer of the following composition:
Two-thirds rottenstone mixed with one-third castile soap, worked into a
paste with a few drops of water so that, although not a liquid, it can
be spread out at will.
Make the wheel move backwards and forwards between the fingers while
resting on a smooth, good cork, without a linen rag, and, as the
operation nears its completion, a semicircular motion should be given
to the wood. Wash with soap, boil in alcohol and dry.
The wheel can be burnished on a cork without any linen rag and the
(curved) burnisher should be moved with short circular strokes from the
center towards the circumference, gradually working up towards to the
extremity of the burnisher; the same portion of the burnisher should
not pass twice over the wheel (see also article =166=). For common
work, fairly satisfactory results may be obtained by using French chalk
and a piece of hard wood.
Clock wheels are polished with a piece of felt and rottenstone. They
are subsequently soaped, washed and dried in sawdust. (=151=)
=186.= =To polish lever escape-wheel teeth.= The Lancashire
escape-wheel makers employ a triangular frame carrying at its corners,
(1) a cutter to slit the teeth, (2) a cutter to shape them, and (3)
a revolving piece of hard leather of a section corresponding to the
form of the space. This latter is charged with the finest glossing
stuff, used dry, and the sides of the teeth of six wheels at a time are
polished by revolving the disc in each of the spaces in turn. It is
hardly necessary to observe that the operation is completed before the
wheels are removed from the cutting engine.
=187.= =To polish sinks or oil-cups.= A piece of pegwood, rounded at
the end, is used for this purpose, rotating it in a lathe; the watch
plate or cock should be inclined in varying directions to the stick in
order to remove scratches. If a very high polish is required it may
be given by following with a stick, the end of which is covered with
wash-leather charged with rouge.
TO POLISH STEEL.
=188.= The polishing must always be preceded by a very thorough
smoothing, either with oilstone dust, fine emery, or coarse rouge. If
any lines are left to be erased by means of fine rouge, the operation
becomes tedious and is rarely successful. The oilstone dust is applied
on an iron or copper polisher. When it is desired to preserve the
angles sharp, at a shoulder for example, the polisher should be of
steel.
When using diamantine an iron polisher, drawn out and flattened with a
hammer, answers very well.
With fine rouge, a bronze or bell-metal polisher is preferable
for shoulders; and, for flat surfaces, discs or large zinc or tin
polishers, although glass is preferable to either of these.
After each operation with oilstone dust, coarse rouge, etc., the
polisher, cork, etc., must be changed, and the object should be well
cleaned—preferably by soaping; perfect cleanliness is essential to
success.
Fine rouge or diamantine should be made into a thick paste with oil; a
little is then taken on the polisher or glass and worked until quite
dry. As the object is thus not smeared over, a black polish is more
readily obtained, and the process gets on better if the surface is
cleaned from time to time.
=189.= =To get a good black polish.= As just pointed out, this is
mainly secured by using very little polishing material at once, in a
very little liquid on either, the polisher or glass plate and drying
up quickly. If the surface does not prove satisfactory at first,
it will often be found that a final rapid and light application of
dry diamantine or rouge on a piece of glass or pith will produce a
brilliant black polish.
If operating on an axis or staff, polish as well as possible, first
erasing the marks of the graver or file, and then, hold the ferrule
between the fingers, rotate it with one hand and with the other rub the
axis lengthwise with a pegwood stick charged with rouge or diamantine.
A rod will show a black polish if it be rubbed lengthwise with emery
paper of gradually increasing fineness, oil being applied with the
finest quality.
_To polish flat surfaces._ Place the object on a sound piece of cork
covered with a clean rag and rub with, a long strip of ground glass.
_To polish a square shoulder._ Fix a rod in place of the T-rest of
the turns, and set it in such a position that the polisher rests on
this vertical rod when lying flat against the shoulder. Another and
better method consists in cementing or otherwise fixing in the plane
of the shoulder a brass disc of such dimensions that the polisher is
constrained to remain flat.
_Observations._ The corner of the polisher that is used for polishing
a shoulder should be neither right-angled nor too acute. In the first
case it would round off the shoulder, and in the second it would become
soon distorted and leave dull radial marks on the surface.
Diamantine should not be used for polishing the acting surfaces of
pivots, the pallets of escapements, etc., since this material, as well
as emery, is liable to leave particles embedded in the steel which
occasion rapid wear.
CEMENT, WAX, RESIN, ETC.
=190.= The principal uses to which the watchmaker applies cement is
for fixing objects in the lathe, pallet-stones in position, as well as
locking and unlocking pallets, ruby-pins, etc.
The selection of a cement or wax is not a matter of indifference;
fine sealing-wax causes objects to adhere firmly together, but many
of the best workmen prefer refined shellac. Certain kinds of wax are
too dry, the consequence being that a false stroke of the graver will
often detach the piece; others are thick and soft, and are apt to heat
rapidly under the action of the burnisher or polisher, so that the
object is displaced. It is only by making a series of trials that the
efficiency of the material can be ascertained. Some workers claim that
a mixture of sealing-wax and shellac gives good results.
=191.= =Mode of applying cements.= When employing wax, resin, cement,
etc., for uniting two objects, it is important to note that the mode
in which it is applied has an important influence on its efficiency.
The following observations on this point are due to M. Sibon, and the
reader will be able to select those portions that have reference to his
work.
When two objects are united by a cement, this will lose much of its
value if unskillfully applied, and, in order to use it to the best
advantage, the following practical rules should be observed.
1. The surfaces to be united must be quite clean.
2. The less cement, wax, etc., that is interposed between them, the
better they will adhere. This is owing to the fact that with a thick
layer the object has, at the junction, no more rigidity than that of
the cement itself; as a rule this more fragile than the material it is
employed to unite.
3. There should be perfect contact between the cement and the surfaces.
With a view to securing this, the object must be first heated to a
point such that the wax or cement cannot solidify without having first
had time to effect a perfect union.
This remark is especially applicable when using sealing-wax, mixtures
of resin, shellac, and similar materials. They will not adhere firmly
unless the surfaces have been heated very nearly to the point of fusion
of the cement. The sealing of letters offers an example in proof of
this assertion. When the seal has been used several times in succession
or been left too long on the wax so as to become hot, it will adhere
and cause some inconvenience if further employed.
With hot melted glue, adhesion is best secured by friction or a
moderate pressure.
Sealing-wax is excellent for uniting metal to glass or stone, providing
they are sufficiently heated to melt it; for, if applied to cool
surfaces, it will not adhere at all. By heating two pieces of glass or
stoneware sufficiently to melt shellac, a small quantity will suffice
to make them adhere firmly together; notwithstanding that every one
has seen such joints, very few succeed in making them, for the simple
reason that they do not recognize the necessity of heating a delicate
piece of glass or china to the point which is essential for securing a
good result.
In conclusion, the principal obstacles to adhesion are air and
dirt. The first is always present; the second is due to accident or
carelessness. All surfaces are covered with a thin layer of air that is
very difficult to remove; its influence prevents highly polished metal
from being moistened when immersed in water. So long as this layer of
air is not displaced, the cement cannot adhere to the surface to which
it is applied, because it cannot come into direct contact. The most
effective agent for displacing this air is heat. Metals heated to about
75° C. (170° F.) are immediately moistened on being plunged into water,
hence it follows that, as regards cements that are applied in a fused
state, heat is the best means of bringing them into intimate contact
with the surface.
We would add that, in addition to possessing this advantage, the
application of heat also renders the surfaces more penetrable to
the layer of cement, after the manner of soldering, and makes the
interlocking of the molecules more perfect; this explains the greater
degree of tenacity of a well made joint with only a thin layer of
cement.
=192.= =To set in wax in the lathe.= Trace a series of concentric
circles on the face of the chuck with a graver point, after turning it
true: this will increase the adhesion of the cement. Then the flame of
the spirit lamp is held under the rotating chuck and, when this is hot
enough, its surface is covered with a layer of shellac or sealing-wax,
and the object is held against it. Holding it in position with a piece
of pegwood supported on the T-rest, the lamp is removed and the lathe
kept rotating until the cement sets. The cooling can be hastened by
applying a small moist sponge, but it should not set too suddenly.
If the object requires to be very exactly centered, its position must
be insured while the cement is still soft by means of a long pegwood
stick in its central hole. This stick is held in position until the
cement sets, steadying it between two fingers close up to the chuck.
The slightest eccentricity will be indicated by a motion of the free
end of the stick.
If the object is round, and has no central hole, it must be centered
by its circumference, holding the pegwood in front, or resting against
a corner of a circular elevation or depression, as, for example, the
collet of a wheel, or of a cylinder riveted to its balance, etc.
The beginner should make a number of trials; they will enable him both
to acquire lightness of touch, and to recognize the proper degree of
softness of the cement for centering, as well as its tenacity.
When it is essential that the two faces of the object be strictly
parallel, a precaution is necessary; this consists in leaving on the
face of the chuck a slightly projecting circular rim with a fine smooth
edge, and of a diameter rather less than that of the object. By moving
this latter backwards and forwards after applying it to the wax, and
pressing it into close contact while cooling, the requisite parallelism
will be secured.
=193.= =To fix a pallet-stone, etc., in position.= To fix a
pallet-stone or an end-stone by means of shellac it is usual to place
a small piece of the latter round the stone when in position and
apply heat. But very often the lac spreads unevenly or swells up; and
this, in addition to being unsightly, is apt to displace the stone.
The inconvenience can be avoided as follows: The pallets are held in
long sliding tongs, and, taking a piece of shellac, heat it and roll
it into a cylinder between the fingers; again heat the extremity and
draw it out into a fine thread. This thread will break off, leaving a
point at the end of the lac. Now heat the tongs at a little distance
from the pallets, testing the degree of heat by touching the tongs with
the shellac. When it melts easily, lightly touch the two sides of the
notch with it; a very thin layer can thus be spread over them, and the
pallet-stone can then be placed in position and held until cold enough.
The tongs will not lose the heat suddenly, so that the stone can easily
be raised or lowered as required. The projecting particles of cement
can be removed by a brass wire, filed to an angle and forming a scraper.
To fix an end-stone, the cap must be held by its edge in the sliding
tongs, and shellac carefully applied around the edge of the hollow. It
is advisable to hold the cap in a small tool formed of two parallel
blades, as when reversed so as to press the stone on a flat surface,
the shellac will spread over the end-stone, from which it will be
removed with difficulty.
ENAMEL.
=194.= This name is applied to an opaque glass, with which various
metallic compounds, such as oxide of tin, phosphate of lime, borax,
etc., have been incorporated by fusion. The color, of course, varies
with the substance so added.
Willis recommends the following as a good white enamel for dials:
silver sand, 14 parts; borax, 10 parts; red lead, 18 parts; niter, 2
parts; oxide of tin, 12 parts; flint glass, four parts; and binoxide of
manganese, 1-50th of a part. But a good deal of care is requisite, both
in selecting the materials and preparing the enamel, in order to insure
a pure color of any desired shade; it is, therefore, often desirable to
purchase the enamel ready prepared.
In applying enamel, regard must be had to the relative dilatation of
the metal to which it is applied, the two being so combined as to
expand and contract together; otherwise there is danger of the enamel
cracking, either at once or shortly after it has set.
Enamel may be applied to gold or copper. Associated with the latter,
it forms the ordinary dials of watches and timepieces, and, with the
former, it serves for making enameled gold dials or cases. The gold
should be of 22 carat, the 2 carats of alloy consisting of equal parts
of silver and copper. If the gold is of a higher standard, it will
not adhere so well, and, if lower, there will be a further danger of
melting the metal before the enamel is fused.
Silver is apt to cockle on the application of heat, and enamel applied
to it presents a bubbly appearance.
=195.= =Application of enamel in the cold.= We are indebted for the
following particulars to M. Fournier, of Dieppe, a well-known enamel
maker:
There are two kinds of false enamel for application, when cold, to
damaged dials.
The first, a mixture of white resin and white lead, melts like
sealing-wax, which it closely resembles. It is advisable, when about to
apply it, to gently heat the dial and the blade of a knife, and, with
this, to cut a piece of enamel of the requisite size and lay it on the
dial. The new enamel must project somewhat above the old. When cold,
the surface is levelled by scraping, and a shining surface is at once
produced by holding at a little distance from the flame of a spirit
lamp. It is necessary to be very careful in conducting this operation,
as the least excess of heat will burn the enamel and turn it yellow; it
is, however, preferable to the following, although more difficult to
apply, as it is harder and does not become dirty so soon.
The second false enamel contains white lead mixed with melted white
wax. It is applied like a cement, neatly filling up the space, and
afterwards rubbing with tissue paper to produce a shining surface; if
rubbed with a knife blade or other steel implement its surface will be
discolored.
PRECIOUS STONES.
=196.= The principal precious stones used in watches, chronometers
and regulator clocks, in their order of hardness, are: diamond, ruby,
sapphire, chrysolite.
A watchmaker, although he may not have had any previous experience
of jewels, can easily ascertain their relative hardness by rubbing
one against the other. The softer will be scratched by those that are
harder, and the stone that can be marked by a file may be thrown aside
as useless.
=197.= =Diamond.= We shall make a very brief reference to this
stone, as it is not used except for the end-stones for balances for
chronometers and high-class watches.
Splinters of diamond are employed for drilling materials of a less
degree of hardness, and fragments fixed at the end of a rod are used
for turning very hard steel; diamond dust is the principal material
used for working precious stones, polishing, etc. (see articles =165=
and =169=).
=198.= =Ruby.= This jewel, of a rich, velvetty, red color, exists in
three principal varieties: oriental, spinel and balas rubies, which
differ as regards their chemical composition.
From a jeweler’s point of view, the value of a ruby is enhanced by its
rich color and transparency; but this is not the case in regard to its
application in horology, for which hardness and capability of taking a
high polish are mainly necessary.
The specific gravity of the three varieties is: oriental, 4.2; spinel,
3.7; balas, 3.6.
The first of these is the best, since it is the hardest, both taking
a better polish in the first instance and retaining it for a longer
period.
In comparison with the other varieties, its specific gravity is greater
and it possesses a brighter color, but will often be found to be less
transparent.
Spinel and balas rubies are frequently met with that are very beautiful
to the eye, but their hardness is inferior to that of the sapphire
and even of the chrysolite. They must be carefully excluded from all
good work, for, either in consequence of the inferior hardness or the
mode in which the oxide of iron, magnesia, etc., is combined, or of
other causes, oil rapidly deteriorates in contact with them, and the
moving parts, especially if they are of steel, soon show signs of wear.
The rubies themselves also suffer, and it is by no means uncommon,
especially in the case of the duplex escapement, to meet with such
jewels quite rough and even pitted on their acting surfaces.
=199.= _False ruby._ In a certain class of watches, a variety of stones
pass for rubies that are known to jewelers as rubicelle, rubace, rock
ruby, Brazil, Siberian or Bohemian ruby, rose ruby, etc., the hardness
of which is even less than that of rock crystal. Pivot-holes made of
these imitations of the real ruby are worth less than plain brass
settings.
=200.= =Sapphire.= The color of this stone, sometimes even milky,
passes through all the shades of blue. Like the ruby, there are several
varieties that differ appreciably in regard to hardness. The hardness
of oriental sapphire is equal to that of oriental ruby; both consist of
nearly pure alumina, colored by a little oxide of iron; their chemical
composition thus being the same, they only differ in regard to color.
It is, then, a great mistake on the part of watchmakers to prefer
spinel or balas rubies in place of oriental sapphires.
The sapphire is more brittle than the ruby.
The other kinds of sapphire, such as water sapphires, are not true
sapphires; they are soft and should never be used in horology. The
density of the oriental sapphire is about 4.01, whereas that of other
kinds is only 2.58.
=201.= =Chrysolite.= Under this name lapidaries include a variety of
stones of yellow-green, apple-green with shades of yellow, and other
colors.
That known as oriental chrysolite, which is the same as the oriental
topaz, has a beautiful pale yellow color with shades of apple-green; it
is the most highly esteemed. This stone has a sufficiently high degree
of hardness for use in watchmaking, as it will scratch rock crystal.
Its density varies from 3.73 to 3.00.
The other varieties, ordinary chrysolites, come very low in the scale
of hardness. They can be scratched by quartz, rock crystal and even by
the file, and are thus of no use for watches.
=202.= =Agate, Carnelian, Topaz.= Only the varieties of the stones
already considered that are termed oriental can be used for the
pivot-holes or the pallets of astronomical regulators, but for the
escapements of the ordinary timepieces of commerce, such, for example,
as the pallets of Brocot escapements, the topaz, agate or carnelian
may be used. When of the hardest kind, and capable of receiving a high
polish, they will very efficiently resist the friction of brass teeth.
As to the softer kinds, they are inferior to hardened polished steel
for pallets.
WORKING IN PRECIOUS STONES.
=203.= The methods adopted for working in the precious stones are in
great parts kept secret by those who practise them; it is, however,
well known to watchmakers that jewels are usually worked and polished
with powdered diamond, and the following details will afford all the
information necessary to enable the reader to make a jewel of any
required form. Where not otherwise stated, the information is taken
from a work published by N. Dumontier.[5]
=204.= =Tools for working jewels.= These are all of simple
construction, and can be made by any watchmaker if, indeed, he has not
them already to hand.
[Illustration: _Fig. 47._]
(1.) A small lathe arranged to receive chucks, fixed to the bench or in
a vise, and driven by a foot-wheel. Its form resembles that shown in
fig. 47.
(2.) Two circular laps of copper and one of tin about 2 inches in
diameter and ⅛th inch thick; these present a flat face for grinding,
smoothing and polishing the stones, and are adapted to the nose of the
lathe.
(3.) A small barrel (that also screws into the nose of the lathe) with
six brass covers, perforated at the center, on which to cement the
jewel-holes, when enlarging, smoothing and polishing their holes.
(4.) A flat steel circular cutter half an inch in diameter, for
slitting stones. Also two similar discs, one of copper and the other of
tin, of the same size, and having sharp edges, are occasionally useful.
(5.) Two small laps, one of copper and one of tin, to smooth and polish
cylindrical stones. These laps are mounted in place of the T-rest,
or in the slide-rest, in such a manner that they can be rotated in a
horizontal plane by a bow, in a manner sufficiently indicated by fig.
48.
[Illustration: _Fig. 48._]
(6.) Two chucks adapted to the lathe, on which to cement the jewels for
drilling, turning and polishing.
(7.) A number of small broaches, spindles with concave and convex ends,
etc., for smoothing and polishing jewel-holes, convex and concave
surfaces.
There may also be added a small steel plug mortar for powdering the
diamond (=169=), and a flat steel plate with a block for working up the
powder.
=205.= =Selection of Stones.= This is of the first importance. By
the aid of a powerful lens, or a microscope, ascertain that they
contain no cracks, air cavities or black specks; avoid stones that are
milky, preferring such as are marbled, and in which the directions of
crystalization seem to cross one another, as they are the hardest. The
hardness may be tested by trying them one against the other (=122=),
but an experienced workman needs only to note the amount of resistance
it offers to the operation of cutting on the lap. The density also
affords a valuable means of determining the nature of stones. (See
above notes on the several kinds.)
=206.= =To find the axis of crystallization of a stone.= It is well
known that jewels differ from glass, in that they form crystals of
certain definite forms; they are therefore termed “crystalline,”
whereas glass is “vitreous.” If a jewel-hole is drilled in any
direction other than the axis round which the crystal may be assumed to
have been formed, there will be difficulty experienced in the drilling
and polishing; the edges of the hole will become rough during the act
of rounding them off, and the hardness will appear to be irregular.
This point seems, however, to be ignored by the majority of jewel-hole
makers, although the determination of the most suitable direction
presents no difficulty.
Obtain, from any optician, two tourmaline plates cut parallel to their
axis of crystallization and with their faces polished. Mount them
in a light frame, parallel to each other, so that each can rotate
independently of the other round the axis through their centers; it is
convenient if a light spring tends to bring the plates together so that
a stone can be held when placed between them. Or such an arrangement
can be bought ready made at most opticians: it is known as a tourmaline
polariscope. If this instrument be held up between the eye and a light,
and one plate be rotated while the other remains stationary, it will be
seen that the light becomes gradually greater or less according to the
direction of rotation; and further, if the plates be good ones, a point
will exist at which there is nearly total darkness.
To examine a stone, cut and polish on it two parallel faces
approximately at right angles to the axis of crystallization; this can
generally be roughly guessed at by inspection. Place it between the
plates (when set at their darkest position), and not only will the
light be in part restored but beautiful colored rings will be formed.
If they are circular, the faces of the stone are at right angles to
its axis; if not, incline it till the rings become so, and the axis
will then coincide with that of the instrument. In case the rings are
not observed at all, the stone must again be cut at right angles to
the original direction, and the experiment repeated. If they still do
not appear, the stone is unsuitable for drilling, but may be used for
pallets, locking-stones, ruby-pins, etc.
The stones to be examined in this manner must be larger than those
commonly met with, and if cylindrical rubies can be obtained they are
to be preferred, as it is then only necessary to slice them across
their axis.
It should perhaps be observed that these precautions can only be taken
in making jewel-holes for the higher class of clocks, chronometers and
watches. The cheaper class must of necessity be cut in such a manner as
their figure may suggest.
=207.= =Making jewel-holes.= Having selected 20 or 30 stones of about
the same height, cement them to a smooth brass or copper-plate, heated
to melt the cement. Hold this plate in contact with a revolving copper
lap in which the coarser quality of diamond powder (=169=) has been
embedded by means of a hard steel block; the lap is moistened with
water.
When one side of the stones is true, soften the cement and, after
washing, place them in a vessel containing spirits of wine heated by
a lamp. After doing the same to the plate, again cement the stones to
it with the trued sides downwards, and grind the other faces until
the desired thickness is arrived at. Clean the stones and smooth them
on the brass lap charged in a similar manner with a finer quality of
powder.
The stones are now ready for drilling. This may be done with diamond
powder, or with the diamond drill, both of which methods will be
explained.
=208.= _To drill with powder._ In drilling with powder, the stone is
fixed with sealing-wax or shellac on a carrier that is adapted to the
tool-holder of the slide-rest, this carrier being provided with a
vertical slide, so that by the screws in three directions the stone can
be accurately centered; it is, moreover, so arranged that the stone can
be advanced to or from the drill by pressing with the finger axially.
Drill a small hole in the center of the chuck and, after fixing a piece
of steel in it that has been hardened and tempered to a greyish color,
turn a point on it about twice the length of a pivot, to serve as a
drill. This point must be slightly thinned backwards to prevent it from
choking in the hole and its end should be flat, so as to retain the
powder.
When the stone is exactly centered, place No. 2 diamond powder on the
end of the drill, and press the stone gently against it, constantly
releasing it from the drill for an instant at a time. The hole will
be perforated in from 8 to 15 minutes, according to its depth, during
which interval the powder should be renewed two or three times. Remove
the stone and fix it on the barrel-chuck cover so as to turn true in
the lathe; then turn out the oil-cup with a diamond graver of suitable
form. See again that the stone is central, and re-center it if this be
found necessary. This is done with the smooth conical end of a soft
round broach, or a pegwood, a lamp being held under the chuck at the
same time.
=209.= _To use the diamond drill._ Having centered the stone on the
chuck, as explained in the preceding paragraph, set it in rotation
and bring a sharp-pointed diamond graver against its center, pressing
lightly and resting the handle on the =T=-rest; a minute central mark
is thus made in the stone for maintaining the drill axial. Selecting
a diamond drill of convenient diameter, moisten it in the mouth and
present it to the mark, applying a gentle pressure, the amount of
which can only be ascertained by practice. It is to be observed that a
number of stones should, if possible, be drilled at the same time, for
the hand is apt to lose the requisite knack, if only one or two are
perforated at a time.
=210.= =Smoothing and Polishing.= When the hole is made through,
remove the stone and invert it on the chuck. The diameter being less
than that ultimately required, pass a brass broach charged with No.
3 powder through the hole, giving it a gentle axial motion while the
stone revolves, and taking care to avoid pushing it so far forward as
to lock in the stone, and holding it very lightly between finger and
thumb. When sufficiently smooth, clean with rotten wood or soft bread,
and treat it in a similar manner with a copper broach and No. 4 powder.
Then again clean and use a tin broach and powder No. 5. Next, taking
a small bone cone, smooth the angles of the holes; then use a copper
wire with rounded end for smoothing the oil-cup (with powder No. 3);
follow as explained for the hole with the finer degrees. Using a finely
pointed pegwood that passes through the hole, _marry_ or round off the
internal angle between the hole and oil-cup (the powder that remains
in the hole being sufficient for this purpose) and do the same to the
outer circumference of the cup with a copper spindle of somewhat larger
diameter.
Round off external angles with a diamond graver followed by a copper
polisher, the end of which is cup-shaped. The flat face of the stone is
polished with a small copper disc and No. 4 powder, pressing it lightly
with the finger at the same time that a circular movement is given to
it; finish with No. 5 powder. Or the stone may be detached and the flat
face polished by working on a ground glass plate, a pegwood point being
passed into the hole to form a handle.
Re-set the stone, inverting it, on the chuck, centering it. The other
side is then polished in the same manner, using such tools as its form
may require.
Having thus completed the stone, examine it carefully with a powerful
glass to ascertain that the hole is highly polished and the angles
rounded off, etc. It is then ready for setting.
=211.= =Setting Jewel-holes.= Whether it be a plate, cock or bushing
in which the stone is to be set, the piece must always be cemented
to a chuck and the hole accurately centered. Turn it out to a depth
corresponding to the thickness of stone, and make a circular groove
round the hole thus made with a round-pointed graver, only leaving a
very thin fillet of metal on the inside. The stone should fit easily
in the hole, but without play, and should pass in to such a depth that
its surface is slightly below that of the plate, etc., when there is
an end-stone; in other cases it must, of course, often depend on the
end-shake to be obtained. At the same time it appears desirable that it
always should be slightly below.
Clean out the setting and place a small quantity of oil in it to
prevent the stone from flying out when made to rotate; or it may be
rendered still more safe by a pointed pegwood held in the hand. The
stone is fixed in position with a small conical burnisher (as, for
example, the point of a round broach) very carefully polished, so as
to avoid all abrading action; if an excess of metal is forced over the
surface of the stone, it is removed with a graver. The surface of the
brass is finally smoothed with pith or pegwood, and tripoli in oil,
followed with polishing rouge in spirits of wine.
English jewel-setters often do not turn the groove, but leave a
projecting edge round the hole, which is pressed on to the stone with a
burnisher.
=212.= =To Make End-stones.= The details already given will enable any
intelligent workman to make end-stones. If one of diamond in a brass or
steel setting is required, take a small rose-cut stone, turn out a hole
in the chuck to receive it, and, after cementing in position, turn off
the corners with a diamond graver so as to be able to set it.
For making end-stones of ruby, sapphire or chrysolite, flatten a face,
using the laps Nos. 1, 2, and 3 in succession, or a plate of ground
glass. Then cement with the flat face towards the chuck, and turn to
the requisite form with a diamond graver. Polish with the cup-ended
brass and copper spindles, and set, if requisite, in the same manner as
a jewel-hole.
=213.= =To make pallets, unlocking pallets, etc.= This may be done
on the lap, or by using files of soft steel, copper and tin. In the
first case the stones are roughed out while held by the hand, and the
required form is given them while holding them in a small carrier that
fits into the T-rest support, but the forms of such stones are so
various that no special details can be here given. The diamond powder
of different degrees of fineness is used, as in making jewel-holes.
=214.= =To make semi-cylindrical locking stones, ruby-pins, etc.= The
stone must first be made approximately cylindrical on the lap No. 1,
so that it may be turned with the diamond graver. Drill a hole in the
chuck, cement the stone in it and turn it in this manner. When true
and of the requisite length and diameter, round off the outer end and
smooth with a cup-ended spindle, then polish with powders 3 and 4
successively. Round off the sharp corner with a cup of rather greater
curvature. The cylindrical surface is polished by means of a small lap
carried on a vertical spindle in a frame fixed in the T-rest support,
and caused to rotate rapidly with a bow, the lathe-head also revolving
at the same time (=179=). The lap-carriage should have a vertical screw
adjustment so that it may be brought just into contact with the stone;
it is supplied with the several degrees of powder in turn. Now drill
a hole in another chuck of the diameter of this cylinder, fix it in
position and finish off the opposite end.
To form the flat face along the axis of the stone it is cemented to a
support in place of the =T=-rest and brought against the revolving lap
in the lathe; or the same result may be attained by using a brass file.
=215.= =To make a duplex roller.= At the present day this operation
so rarely has to be done that only a few words can be devoted to its
consideration.
Very pure rubies must be selected, and the hole drilled as explained
in =209=; if the drill is too short it must be introduced at opposite
ends, and the two holes made to meet. After smoothing the surface, the
notch is cut with the thin steel cutter referred to in article =204=,
the roller being cemented to a support that replaces the T-rest. When
the steel disc charged with powder No. 4 is revolving very rapidly,
advance the roller under it by a screw. The notch is polished by a
small copper file of suitable form, and its corners rounded off by a
tin one of square section, one edge of which enters the notch.
=216.= =To mount diamond drills and gravers.= Drill a hole or file
a notch in the end of a piece of brass wire to correspond with the
fragment of diamond; heat the end in a spirit lamp and lay on it a
piece of good sealing-wax or shellac. When this commences to melt, set
the diamond in position and leave the whole to cool. Diamond drills are
very commonly mounted at the end of a pin that has had its point filed
off; mark a point on the end with a graver and drill the hole, which
should be very shallow. Holding the pin in a pin-vise with its point
projecting about 1-10th inch, heat the vise in a lamp, and proceed as
above explained.
FOOTNOTES:
[4] The theoretical density of an alloy, on the assumption that in
alloying the metals do not contract or expand, is obtained by dividing
the percentage proportion of each constituent metal by its density,
adding the products so obtained together, and dividing their sum into
100.
[5] _L’art de travailler les Pierres precieuses a l’usage de
l’Horlogerie et de l’Optique._ Paris. 1843.
PART III.
HEALTH AND MANIPULATION.
PRESERVATION OF HEALTH.
=217.= Some of the following directions may perhaps be considered to
be over-minute and too restrictive; but they are not so. Good habits
contracted in youth are easily maintained, and, when the watchmaker
has tried them long enough to convince him of their influence on his
health, he will experience no difficulty in keeping them up.
THE SIGHT.
=218.= When working at any small mechanism, such as a watch, it is
necessary to use the glass, but this practice is apt to produce
inflammation of the conjunctiva or cornea and a weakening of the
eyesight; a too frequent and prolonged use of the glass will have the
same effect as using spectacles that are too strong.
In order to preserve his eyesight, the watchmaker should take the
following precautions:
He should not retain the glass at his eye by a contraction of the
muscles for more than a brief interval of time. The glass holder, which
can be at once set in any desired position, has therefore much to
recommend it.
Drill a few holes in the frame of the glass to avoid or at least
diminish the inconvenience that arises from the heating of the
enclosed air, as well as from the deposition of moisture on the surface
of the glass.
Do not use glasses of too great magnifying power; they needlessly
fatigue the eye.
Only use glasses that are truly achromatic. If compelled to use the
ordinary simple glass, place a ring of dead black paper inside the
frame and against the lens, which, by diminishing the field of view,
will reduce the inconvenience due to spherical aberration.
It is hardly necessary to advocate the use of a green cardboard shade
to the lamp, as they are so generally used by watchmakers. It should
be so arranged as to protect the head and eyes from radiation, and
cardboard is preferable to metal as it radiates less heat.
Working at night and by artificial light, more especially by the
dazzling light of gas, fatigues the eyes much more than with ordinary
daylight, and the workman will find it a relief, if obliged to work by
artificial light on very minute objects, to rest his eyes frequently
on large stationary bodies. If he can do so, it is a great comfort to
bathe the eyes in cold water.
It is good practice to habituate oneself to the use of either eye with
the glass.
By adopting these simple precautions, how many of our fellow-workers
who are now only able to see objects indistinctly and suffer from
incipient blindness would have preserved their sight uninjured. And
there is yet another precaution that has been pointed out by Dr.
Haltenhoff, of Geneva. He has shown that by avoiding an excessive
indulgence in alcoholic drinks or tobacco, many old watchmakers in that
town have succeeded in preserving their sight unimpaired, and it is
impossible to doubt the truth or over-estimate the importance of this
fact.
The same authority draws attention to the necessity of taking care
that, before adopting watchmaking as a trade, youths should ascertain
that they do not suffer from progressive nearsightedness, which is
often hereditary, as in such a case they would most certainly be
compelled to abandon it in after life. Boys should not be set to work
on such small objects as the details of a watch too early in life,
before the membranes of the eye have assumed a certain degree of
rigidity.
Mr. Brudenell Carter, a well-known ophthalmist, is of opinion that the
habitual use of the glass by watchmakers has the effect of actually
developing and preserving the power of the eye.
THE BODY IN GENERAL.
=219.= It is often found that an old, or even middle-aged watchmaker is
irritable, often tired and soured. This arises, not so often from an
over-excited uneasiness in regard to his trade, an explanation that is
usually urged, as from a derangement of his digestive organs brought
about by the habit of life he is compelled to adopt. Prolonged working
at minute horological mechanism is perhaps more wearying to the mind
and body than any other trade or occupation.
To avoid its ill effects the watchmaker should adopt the following
precautions as far as possible:
Do not use a stool with a stuffed seat, but prefer one of cane or wood.
Take care that the relative heights of the board and stool are such
that an excessive compression of the muscles of the chest, etc., is
avoided during any long operation that renders it necessary to maintain
the body in a constrained position.
A stool with adjusting screw similar to a music stool is convenient
from this point of view.
Change the position as much and as often as possible, especially when
working with the file or graver. With this object in view many workmen
have a second board of such a height that they can work standing.
When using the lamp let it always be provided with a cardboard shade as
already recommended.
A screen to protect the head from the direct heat of the flame is often
found advantageous; in fact, the watchmaker should adopt the advice of
Boerhaave: “Keep the head cool and the feet warm.”
Let him always remember that nothing does more harm than sitting to the
bench immediately after a meal. He should allow an interval of half an
hour to elapse and with some temperaments, even this is not enough;
during this period he should only do work at which it is possible to
stand. A little exercise, such as a walk that is not hurried, will
be still better; it will stimulate the circulation and stretch the
muscles that have been maintained in a constrained position for a long
time through the prolonged attention and slight motion that his labors
involve.
USE OF THE FILE AND GRAVER.
=220.= The first operations that a watchmaker ought to learn are to
file flat and square, to turn round, to forge, to hammer-harden a piece
of metal without deteriorating it. These accomplishments are but too
much neglected in the modern training of an apprentice, an omission
that is partly owing to the want of good instructors and partly to the
shortness of the time he can afford to devote to learning his trade.
TO FILE FLAT AND SQUARE WITH BOTH HANDS AT ONCE.
=221.= It is a very common practice to place an old file in the hands
of an apprentice, to fix in the jaws of a vise a piece of metal, either
brass, iron or steel, and to set him to work rubbing and filing the
surfaces with great labor, the only result being that they are utterly
mis-shapen and covered with brilliant spots.
This method is bad. The action of the file is mechanical and the
problem that has to be solved is the following: To produce good work in
the shortest possible time, and with the least expenditure of force.
It is therefore only by very slow degrees that an apprentice can hope
to acquire the requisite ability, if he is set to work trying to shape
an object in some hard metal before he knows how to maintain lines
straight and surfaces flat. Not knowing how to proportion his effort
to the resistance to be overcome, and allowing the file to travel
irregularly over the surface, he gets confirmed in the tendency to give
a rocking motion to the file, whereby the surface is left round, and he
will find it all the more difficult to throw this habit aside.
It is far better to let him commence on round pieces of common wood,
filing with a rasp or coarse-cut file, without removing too much at
once. By this means he may rely on learning to file flat and square by
the eye alone without the aid of a straight-edge.
When he works well in common wood, he can be set to file harder woods,
box for an example, roughing with a rasp and finishing with a new
bastard file. He should not be allowed to have hard wood until able to
file a surface so well that, on placing a metal rule across it in any
direction, it is found to be flat.
=222.= Let him then advance to brass, which, if cast, should be
previously dipped in acid to remove the hard surface, as this should
not be filed off. The resistance it offers would cause a jerky motion
of the file that would be apt to disturb the slight amount of decision
the hand has already acquired.
As brass opposes a considerable resistance, the pupil should be
carefully watched with a view to preventing too rapid movement and an
excessive pressure, involving waste of power, while he fancies the work
is being proportionately advanced; the manner in which the file is
applied to the surface should also be observed, taking care that little
or no pressure is applied during the backward stroke. The teacher
should both explain and demonstrate that the main secret of success
consists in a perfect equilibrium between the actions of the two hands;
one should increase as the other decreases with the horizontal motion
of the file, since the two levers in use, namely the portions on either
side of the point of contact, are continually the one increasing and
the other decreasing.
By filing steadily and attentively, the hands will gradually acquire
the requisite sensitiveness, or tact, that enables each to adjust the
pressure in proportion to the other, as well as the knack that enables
them to maintain the surface flat. It is important to avoid short and
jerky movements.
Practical instruction from a competent teacher must be relied on to
complete the directions here given; no written instructions can replace
it.
It is advisable to use new, or nearly new files in the above lessons;
the wear will have brought them into good condition for working iron or
steel.
Proceed with these metals as already explained in regard to brass, and
special attention must still be given in order to prevent hurry on the
part of the pupil. The files remove less metal at a time and a greater
pressure is necessary, so that he does not make such rapid progress
as with brass, and this gives rise to a tendency either to use new
files, which are soon spoilt, or to give the stroke too suddenly, while
applying considerable pressure, especially during the return stroke. He
thus heats his file, breaks off the crests of the teeth, which become
embedded in the metal and do much to further damage the file. Moreover,
he will lose some of the sensitiveness of touch that his hand has
already acquired.
=223.= It would perhaps be well to subdivide the day into three parts
for as long as appears necessary; the first to be devoted to filing,
the second to turning, and the third to forging and cold hammering.
By this means he will be quicker in acquiring the requisite skill of
hand and eye, and, when he has attained to this ability, it will be
time to practice himself in the management of various tools. Feeling
certain of himself he will soon become quick in his work.
It is prejudicial to the true instruction of a pupil and a false
economy of both time and money, to let him commence either a clock or
watch before arriving at this point. He will experience difficulty
in making even the simplest pieces, which, besides being very badly
made, will take up a long time; he will keep forgetting as he goes on,
because, owing to the slowness with which he works, the construction of
a machine occupies months, or even years, whereas it would only have
occupied a few weeks, or months, if he had possessed sufficient manual
skill to enable him to handle properly the file and graver.
We insist specially on the need of this preliminary training of the
young horologist, because, with very rare exceptions, if a pupil is set
to delicate details before he is master of his tools, he works with a
want of decision, and, therefore, with difficulty. He will, as a rule,
make a workman of but moderate ability, and will soon become disgusted
with his trade, from the mere fact that he cannot work with ease and
rapidity.
Time is an element of success; hence gratuitous apprenticeships for
short terms, that become a tax on the master if he does not soon make
use of his pupil’s services, will very seldom produce good watchmakers.
TO FILE FLAT WITH ONE HAND.
=224.= When an object is to be held on a cork or wood block fixed in
the vise, with one hand, and filed with the other hand, special care
must be taken to lay the file flat without any hesitation after each
return stroke, and the hand should be able to feel if the file is
wrong in this respect, and to at once bring it flat. After the pupil
has learned this, he will very soon be able to adjust the pressure and
the force exerted in moving the file horizontally, so that it shall
remove an equal amount from the entire surface operated upon. It often
happens that the object can conveniently be rested upon a finger of the
left-hand while the right-hand holds the file. The maintenance of the
file flat is in that case much easier.
=225.= _Mechanical device for filing flat._ This (the _pradel_)
consists in placing behind the workman a horizontal bar, on which rests
one end of the file handle, prolonged for the purpose to about a yard
in length; thus the file has two points of support: the bar, adjusted
at a convenient height, behind the workman, and the object to be filed
flat fixed in the vise in front.
This method, while convenient for amateurs, may be utilized in teaching
an apprentice, letting the supports be hinged at one and press at the
other end on a rather strong spring index, which must be prolonged so
as to be brought under the eye of the pupil.
The displacement of the index will show him every false movement of his
hands, and will guide him in adjusting them. It would be best if the
prolongation of the handle were as light as possible, but rigid and
arranged so that the file can be held naturally.
TO TURN CYLINDRICAL PIVOTS, ETC., AND SQUARE SHOULDERS.
=226.= Just as in working with the file, advice and demonstration by a
good master are here indispensable.
The materials should be worked in the same order as is explained in
parts =221-4=; that is: wood, brass, iron, steel, hardened and tempered
steel; no one sample being set aside until the student can turn it
perfectly round, flat on shoulders, etc., and smooth throughout.
He should turn for a long time, whether it be by the lathe or bow,
exclusively with the point of a square, or lozenge-shaped graver, the
end of which is ground off on a slope; this is the only possible method
of learning to turn true, and it enables the workman to acquire great
delicacy of touch.
Owing to carelessness, or to the fact that, when first beginning, they
were set to work on metal that was too hard or rough, most learners
turn with gravers that are ground to very blunt points; as the graver
bites less, they are obliged to apply a proportionately increased
pressure, and only succeed in tearing the metal away, subjecting it to
a kind of rolling action, and rendering the hand heavy. If a pupil will
not practice turning with the graver point, so as to preserve it intact
for some time, dependent on the nature of the metal, he will never be
able to turn perfectly true.
The bow should be used through its entire length, and with a motion
that is progressive, not jerky. The knack of the turner with the
bow consists mainly in keeping the simultaneous actions of the two
hands quite distinct; one drawing the bow downwards, while the other
depresses the point of the graver supported on the =T=-rest, and these
two movements of the hands must be performed at the same time, but
quite independently.
Irregular and sudden depressing of the graver point, or engaging it
too deeply, causes its frequent rupture. This also sometimes arises
from the fact that the point is not removed with sufficient rapidity,
so that on raising the bow the metal catches it while traveling in the
reverse direction; the graver is thus drawn slightly towards the work,
and its point will be found too close in when the bow again descends.
As has been already observed, the bow, which must not be too short,
should be used to its full length with a regular, but not rapid motion.
Afterwards, when the hand has learnt how to manage the graver, the
speed can be gradually augmented. There is always a danger of losing
time, teaching, and, therefore, money, if pupils are too much hurried
in their lessons. Before trying to work quickly, they should, at any
rate, know how to work fairly well.
Short and sudden movements of the bow will make the object turned jerk;
it will be heated, and the sharp angles of the graver will jamb in the
metal; thus there is less work done, although there is more noise, and
this is done badly.
=227.= When sufficient experience has been gained in turning with
the graver point, and a trial is made with the cutting edge, do not
attempt to remove much at a time by pressing heavily, but take the
metal sideways so as to remove a continuous thread, using all the
points of the edge in succession and the entire length of the bow. The
metal will thus be removed as a thin ribbon or shaving. When the hand
has had some experience, it will be found easy to remove long strips,
and the work can be done quickly, although there be no hurrying in the
movement of the bow. These remarks are equally applicable to turning
with a lathe.
=228.= Hardened steel that has been let down to a blue temper requires
certain precautions. If the graver is found not to cut cleanly, it must
at once be sharpened, and no attempt should be made to remove more
metal by increasing the pressure of the hand, because the steel will
burnish and become hard under a point or edge that is blunt, and the
portions thus burnished are sometimes so hard as to resist the best
gravers. The only way of attacking them is to begin at one side with a
fine graver point which must be sharpened for each stroke; at times it
becomes necessary to temper the metal afresh before it will yield. It
is asserted that by moistening the point of the graver with petroleum
it becomes more able to attack hard substances, and that a mixture of
two parts petroleum and one part turpentine enables it to turn very
hard steel with comparative ease. Indeed, for all turning it is a
common practice to moisten the graver with oil, water, turpentine, or
simply by introduction into the mouth.
We have frequently seen apprentices, and even watchmakers, themselves,
careless as to the proper sharpening of their gravers and thinking
that they could hasten their work by the application of considerable
pressure; they thus produced bright spots that required several hours
of work before they could be removed.
There is one essential condition for ensuring good work with the lathe,
and this consists in the perfect roundness of the points or holes of
the runners or centers, and of the holes or points that are supported
in them; this perfect truth is nevertheless very rarely met with, for
it is noticeable that barely one watchmaker in ten knows at the present
day how to roll such a point. We shall subsequently indicate the
precautions to be observed in order to secure this accuracy.
The diameter of ferrule is also to be considered; if it is too small,
the bow will slip and the object will only rotate by jerks; if too
large, it loads the object unnecessarily and the velocity of rotation
is reduced, since for the same stroke of the bow the ferrule must make
a less number of turns. Moreover, if it is of large diameter, only a
light bow must be used, because otherwise the force applied would be
excessive.
Swiss workmen—at least the great majority of them—turn with the right
or left-hand indifferently. This is a very useful accomplishment easily
acquired when young.
The working of various tools, such as the English or Geneva mandrel,
and any lathe driven by a treadle, will be a great help in developing
the sense of touch and in making it more certain.
But it must not be forgotten that, in order to turn well, the lathe
must be well made and planned; without this, no accurate work can be
done. The lathe is the first and most important of tools, and a great
number of very serviceable accessories can be added to it, which,
unfortunately, but few watchmakers know how to make properly. As a rule
they content themselves with a simple pair of finishing turns on which
but a comparatively small amount of work can be done.
Without committing the mistake of having a too great multiplicity of
tools, let the pupil rest certain that a well-planned set of tools in
good condition both facilitates and abridges his work and renders it
more perfect.
PART IV.
TOOLS AND APPLIANCES.
WORKSHOP FITTINGS.
=229.= Before proceeding to describe the various forms of lathes and
the several small tools that the watchmaker should make for himself as
occasion offers, either during his apprenticeship or immediately after,
with a view to increase his manual skill or to extend his experience,
it will be well that he take note of the principal conditions that
should be satisfied by the ordinary tools that he will have to buy,
as well as the precautions to be observed in their use and some
improvements of which they are capable.
=230.= =The bench or board.= This should be fixed in front of a large
window that affords a good light. The various hooks, recesses, etc.,
for holding files, hammers, etc., as well as the drawers, should be
well in sight, not only in order that the hand can at once take hold of
whatever tool is required, but also to enable the workman to restore
them to their place immediately after use. By doing so he will have
no occasion to retain on the bench any but those tools that are very
frequently or continuously used.
It is an excellent habit, conducive both to well-planned and rapid
work, and which can be easily acquired by a little attention during an
apprenticeship, to always place the same tools in the same places, as
the bench will then never be encumbered. By this means loss of time in
turning over a number of objects in order to find one that may be small
is frequently avoided.
This observation is of minor importance to specialists who require but
a small number of tools; but it is of the first importance to a workman
that is engaged in the repair of watches.
=231.= =The stool.= Those with cane seats are to be preferred. The
height of the bench and stool should be so related that the muscles
of the chest are not too much cramped, especially if the workman is
engaged on an operation that occupies a long time and obliges him to
maintain a stooping position. The stool with a screw is advantageous in
this respect.
=232.= =The lamp.= Certain precautions in regard to artificial light
have already been indicated in article =218=.
=233.= =Oilstones.= It is impossible to maintain the points of
gravers in good condition if care is not taken to keep clean and flat
the surface of the stone on which they are set; if it has suffered
irregular wear, the level may be restored by rubbing the stone on a
flat, smooth board, covered with a thin paste of fine sand and water.
Most kinds of oil thicken on the surface rapidly, when the graver will
slide over without being ground down at all, turning around in the hand
and thus destroying the flat face and wearing the softer parts of the
stone, rendering it uneven. A strong solution of potash or soda is very
effective for removing this gummy mass; benzine is also recommended for
the same purpose. Various substitutes for common oil are used; such
as the mineral lubricating oils or petroleum. Dr. Latteux advocates
the use of a mixture of alcohol and glycerine, the proportion of the
latter decreasing as the extent of metallic surface in contact with
the stone at once increases. Thus, for example, in setting a razor the
stone will bite better if alcohol be in excess; but for a graver, of
which only a small surface touches the stone, the amount of glycerine
present should be relatively much greater.
=234.= =Circular oilstones.= Circular oilstones will be found very
convenient for sharpening drills, gravers and other cutting tools,
where it is desirable to have exact angles. An Arkansas or Turkey stone
dressed down to circular form, and say 1½ inches in diameter, when
mounted for the lathe will be found very useful. Apply the lubricant to
the stone the same as you would to a flat one, and hold your graver or
drill at the exact angle you wish the cutting edges to be and turn at
a moderate speed. Truer angles and better work can be produced in this
manner than by any other. Emery or corundum wheels can be mounted in
a similar manner. Small circular stones can be obtained from material
dealers and dental supply houses, in sizes varying from ½ × ⅛ to 3½ × ¾
inches. They can be mounted similar to Fig. 49, by turning down a piece
of No. 30 Stubb’s steel wire to the size of the opening in your wheel
and riveting the wheel firmly upon it. The best sizes for watchmakers’
use are ½ inch, 1 inch and 1½ inch in diameter.
[Illustration: _Fig. 49._]
=235.= =Small grindstones.= When it is necessary to remove a good deal
from the face of a graver, the operation will take too long on the
oilstone, and there would be considerable difficulty in maintaining the
flat face; recourse must then be had to the grindstone, but it should
be remembered that care is needful when using it. The grindstone must
always be thoroughly wet in order to avoid heating the graver, as its
cutting power would then be destroyed. The emery wheels described in
paragraph =165= can be used for this purpose, but they are, for the
most part, inconvenient on account of the rapid increase they occasion
in the temperature of the metal. Some forms of emery wheel can,
however, be moistened just as the grindstone.
When the cylindrical surface is rendered irregular by use, take a piece
of sheet-iron, the tail of an old file or a cold chisel, and hold it
with one hand firmly on a support against the edge of the stone, which
is rotated by the other hand. The surface can thus be made smooth and
true, providing it is only attacked gradually and the handle is not
turned too rapidly. An excessive velocity will heat the iron, which
is then less effective and is more rapidly worn down; whereas, with a
slow motion, the iron will relatively wear little and the stone more.
A rough diamond mounted at the extremity of a steel rod, affords an
excellent means of trimming a grindstone, and is at the present day
generally used in factories.
=236.= =Glasses.= Some particulars have already been given in regard to
these simple microscopes in article =218=.
=237.= =Files.= A new file should never be used for steel; it is best
to employ it for some time at first on brass, taking care not to use it
too roughly. If employed to steel at once, or if sharp, quick strokes
are applied, the cutting edges of the file will chip off, and the hard
particles will be embedded in the metal operated upon; the work will
thus be bad, and the file itself deteriorated. A file that has been
carefully used, and has passed gradually from brass to steel, will last
four or five times as long, and will always work well.
Watchmakers often fit files into handles by driving them firmly into
round holes in the handles; this practice frequently leads to the
handles being cracked, and the following method is preferable: Take
an old worn out file or a piece of iron of the same form as the tail
of the file to be fitted; heat it several times to bright redness and
drive it, when so heated, into the handle, taking care to maintain it
perpendicular. A hole will thus be made of the required form, in which
the file will hold without there being any occasion to apply excessive
force in fixing it in position.
When the surface of a file is choked with particles of iron, copper,
wood, etc., while the cutting edges are yet good, it can be cleaned as
follows: Place the file for a few seconds in a hot lye of potash in
water, and on withdrawal, dry it before the fire and brush the surface
with a stiff brush.
=238.= To renew the cutting edges of files, either of the following
methods can be adopted: 1. First clean the file with potash or soda
dissolved in water, if greasy or resinous substances have to be
removed; with hydrochloric acid if it is rusty; and by rubbing with
a metallic brush or piece of coke if particles of iron, brass, lead,
copper or tin have to be removed. The file is now immersed in a
mixture of 1 part nitric acid, 3 parts sulphuric acid, and 7 parts
water. As the action of the acids become less energetic owing to the
combination with iron, the temperature of the mixture must be raised,
since rapidity is a condition of success. The time during which the
file should remain in this bath varies from 10 seconds to 100 or more,
the roughening of fine-cut files being far more rapid than when they
are of a coarser cut. On removal from the bath, immerse in lime wash,
dry, and then cover them with a mixture of oil and turpentine by means
of a brush, after which they are ready for use. 2. After being cleaned,
as explained above, the file is supported in a dish full of water,
resting on two cross wires, so that all its surface is in contact with
the liquid. Now add strong nitric acid in the proportion of 1 part to 8
of the water, mix it thoroughly and allow it to remain for 25 minutes.
Remove the file, and, after washing in water and rubbing with a hard
brush, place it again in the bath, to which a second eighth part of
acid is now added, and leave it for 50 minutes. Again remove and brush
the file, add a sixteenth part of concentrated sulphuric acid, and
replace the file in the bath. Then wash successively in pure water and
in lime wash (to remove the last traces of acid), and dry. The file
will be found to possess both the qualities and the appearance of a new
one.
=239.= _To cut an equaling file._ It often happens that a workman
is called upon to modify the shape of, for example, the bottom of a
rectangular notch, and he is not provided with a file of suitable
shape. In such a case he can adopt one of the following methods of
extemporizing a file:
[Illustration: _Fig. 50._]
1. Clamping the small steel strip, L, Fig. 50, in a vice, cut the
notches with a chisel, _n_, as follows: Holding _n_ a little inclined,
cut the first notch, _i_. This will slightly raise the metal,
presenting a rounded face at the back. To make the next cut, hold the
chisel with its edge on L and, after drawing it backward until arrested
by the back of _i_, incline it to the requisite amount and give a
second blow with the hammer, then continue the operation till the whole
is finished. A few trials will enable any workman to make a small file
with sufficient accuracy for his purpose.
2. Employ an arrangement similar to that of the micrometer divider
(=44=) only more rigid. A study of this article and examination of the
corresponding figure will afford all the information that is necessary.
3. This is identical with the method of dividing a rule described in
=46=, except that the divisions are closer together and the tracer is
replaced by a revolving cutter with its axis a little inclined, to give
the requisite slope to the teeth of the file. This cutter is supported
in a hinged frame and provided with a washer of ivory or other such
substance, as seen at _s_, Fig. 50, to determine the depth of cut.
=240.= _Beaupuy files and burnishers._ Most watchmakers are acquainted
with the files and burnishers that M. Beaupuy has introduced for
rapidly forming conical pivots, the main characteristic of which is
that the corner presented to the pivot is rounded to the desired form
and roughed; they do their work rapidly and well, but some skill is
necessary in their management. To the instructions which accompany them
we would add the following:
They must never be used when quite new on a pivot that is to be
employed in a watch; it will be reduced too rapidly. The freshness must
be worn off the cutting edges of the teeth by preliminary use.
The pressure must only be applied perpendicularly to the surface of the
staff as in making a square-shouldered pivot; the file is held against
the flat surface without pressure. A lateral force will have the effect
of straining the pivot and causing it to break.
=241.= =Pliers, tweezers, etc.= It is advisable to have a considerable
number of these, as their strength should always be proportional to the
force that has to be applied to them. For example, if a pair of sliding
tongs is used when a hand-vise is needed, the former will be strained
beyond its limit of elasticity and the tool becomes nearly useless.
The same might occur with any other form of pliers or tweezers. In the
hands of a good workman they will last for a long time, but if used
unintelligently, without proportioning the size of tool to the force
that has to be applied, taking up the first that comes to hand, all the
tools will soon become unsatisfactory and the work itself will suffer.
It is very desirable to have one or more pairs of brass pliers and
tweezers for handling metal work without the risk of scratching.
=242.= =Compasses, gauges, micrometers, etc.= The common compass
for measuring thickness, the douzieme gauge, is not always strictly
accurate in its indications. The douzieme proper, has a scale
divided into twelfths, though some patterns are now made that have
a scale divided into tenths and hundreds of an inch and again there
are others that measure the fractions of a millimeter. The greater
majority of these tools on the American market are correctly divided,
but we sometimes come across those of foreign make that are divided
incorrectly and care should be used in selecting. In the inaccurate
tools the objection is that the opening of the jaws gives a measure of
a _chord_ whereas the displacement of the index measures the _arc_ of
a circle. It follows from this, that, if the index is first arrested
when pointing to 15, for example, and again when at 30, the interval
between the jaws in the second case will not be exactly double the
first. Before purchasing, it is well to test the gauge for accuracy in
this regard by some reliable standard.
=243.= _Caliper for mainspring height, depth of sink, etc._ A simple
instrument for taking such measurements is shown at G, Fig. 51.
[Illustration: _Fig. 51._]
The finger _a_ travels over a graduated arc whenever the rod _c_ is
pressed inwards; _b_ is a fixed stop, with its extremity in the plane
of _n_. Any movement of _a_ below _o_ measures the space traversed by
_c_ within the line _b n_.
Laying a coiled mainspring, for example, on a plane surface, stand the
base _n_ of the caliper upon it, and the end _c_ pressing on the table
will be forced upwards and move the needle. To take the depth of a
barrel, press _c_ on the bottom, allowing _b_ to rest on the edge of
the cover recess.
It will be evident, from the figure, that _a_ and _c_ are connected by
a spring passing around drums at corresponding axes. The smaller _j_
is, the more sensitive will the instrument become.
=244.= =Figure 8 caliper.= For ordinary work, the calipers to be
bought at material stores will suffice; but when it is required to
verify escape wheels, balances, etc., there is some risk of accidents
in consequence of the variableness of the friction at the joint. To
remove this source of danger, true the rubbing surfaces in the mandril
and replace the brass discs at the center by similar discs of steel,
then carefully re-make the rivet that forms a hinge, after oiling all
the acting surfaces. The arms will now move with a uniform degree of
stiffness, so that there need be no danger of jerks.
=245.= =Riveting stake and punch.= The holes in a riveting stake are
made to increase downwards, so as to avoid any accident occurring
through the oscillation of the axis. The riveting punches made of a
plain steel rod, with a hole drilled at one end in the direction of the
axis, are the best. Those that are perforated transversely like the
lanterns of screw-point tools, do not produce such good riveting, since
the parts of the end, from behind which metal has been removed, are
more or less elastic.
=246.= =Burnishers.= Burnishers will not remain in good condition
unless their surfaces are prepared, from time to time; in the case of
those used for very fine work, by passing over a buffstick charged with
polishing rouge or very fine emery, and other kinds on an emery stick
more or less fine, according to the degree of roughness the burnisher
is required to possess.
=247.= _To re-face a burnisher._ Pivot burnishers are usually re-faced
by a lapidary; a watchmaker can, however, do it for himself very
effectually in the following manner: Prepare a dry, smooth piece
of wood, rather thick, and of a width equal to the length of the
burnisher. On this board carefully glue a piece of emery paper, of a
fineness corresponding to the degree of cut required, stretching it as
even as possible, and turning the edges down towards the under side.
Then lay the board on a firm smooth surface, resting a weight upon it,
and allow it to dry.
In using this lap, it is fixed or allowed to rest against the side of
the bench; holding the burnisher with two hands at its extremities, the
workman places himself at one end of the board, and draws the burnisher
along it towards him, maintaining the surface quite flat and applying
considerable pressure. On reaching the nearer end, raise it, and after
again placing it on the farther end, draw towards the body, and so on.
By proceeding in this manner and always in the same direction, placing
the burnisher so that the acting edge is farthest away from the
operator, all risk of rounding this angle will be avoided.
=248.= =Broaches.= Great care is needed in adapting handles to
broaches. Resting the point against a finger of one hand and causing
the handle to rotate by two fingers of the other hand, the broach
itself should be seen to remain true.
It is a good precaution, suggested by M. H. Robert, to gently draw a
piece of iron, charged with rouge, along the edges of pivot broaches in
order to remove the thread of metal from them. Minute particles of this
thread would otherwise remain in the holes, and occasion wear of the
pivots.
These fine broaches are not fixed in handles, but a piece of
sealing-wax is melted on to the upper end; then, holding the broach
between the fingers, with its stem downwards, it is rotated while held
to a flame, so that the sealing-wax forms a regular, oblong handle.
=249.= =Blow-pipes.= In order that a long even flame may be obtained,
the hole should be of moderate size and perfectly clean around the
edge; otherwise the jet cannot be straight and sharp. Difficulty will
always be experienced by anyone who has not learned to breathe without
interrupting the continuity of the blast. Where a supply of gas is
available, the gas blow-pipe presents advantages from the point of view
of convenience.
[Illustration: _Fig. 52._]
Fig. 52 shows a gas blow-pipe for jewelers, which is simple and
convenient. It consists of a blow-pipe of the ordinary form, having a
gas pipe inserted in the lower half, and a threaded hood or sleeve at
the lower end, which changes the shape of the flame by screwing in or
out, so as to vary the influence of the current of air upon the flame.
A ring adapted to slip over the finger while working, is soldered to
the middle joint of the pipe, and the quantity of gas is controlled by
the stop-cock and spring lever shown in the cut, the gas being supplied
to the pipe by a rubber tube connecting it to the nearest gas jet in
the usual way. Thus having the shape of the flame under control and the
quantity variable at will, the workman is in position to accomplish the
desired end speedily and effectually.
To use to the best advantage, set the jamb-nut so that with the valve
lever in its normal position, the flame at the end of the pipe will
just keep alight. The blow-pipe can then be laid down temporarily and
again used without the trouble of turning off the gas or relighting.
When used as a mouth blow-pipe, the most convenient way to hold it is
with the third finger through the ring. For bellows work it is better
to pass the ring over the index finger. The ring also serves, with the
valve-lever, as a rest to hold the flame-nozzle away from the table
when the blow-pipe is laid down temporarily.
To produce an oxy-hydrogen flame, connect the air-pipe with a cylinder
of nitrous oxide, opening the cylinder-valve carefully, so as to
permit the escape of only sufficient nitrous oxide to produce with the
illuminating gas a very small flame. Regulate the illuminating gas flow
with the thumb-screw or with the finger on the lever of the blow-pipe
valve.
[Illustration: _Fig. 53._]
Fig. 53 shows an automatic hand blow-pipe for use with a foot blower.
One of the rubber tubes shown is connected with the blower and the
other to the gas supply. It is self adjusting for both gas and air,
requiring only a slight motion of the lever, shown under the thumb, to
obtain instantly any flame, from the smallest to the largest; so that
these pipes have all the delicacy of the best mouth blow-pipe, used
with the utmost skill, together with the power and advantages obtained
with a mechanical blower.
=250.= =Small gas furnaces.= The workman will frequently have occasion
to anneal pieces of steel or to raise to a red heat objects that are
too large for the blow-pipe; an ordinary open fire aided by bellows is
often resorted to in such a case. A better plan, however, is to use
any small portable gas furnace, provided with a hood that completely
closes it at the top.
Fig. 54 shows a gas melting furnace, which is kept by material and
supply houses. It is powerful enough to melt gold, silver, brass and
copper, but is not recommended for cast iron. It can be used for
scorifying and cupelling. The lid can be pushed sideways sufficiently
to give access to the interior of the furnace.
[Illustration: _Fig. 54._]
The following points in the management of a gas furnace will be
of service to all novices in their use. The power and speed are
practically without limit, depending only on the gas and air supply,
and are under perfect control. Allowing five cubic feet of gas for
heating up, it requires about four feet of gas for every pound of cast
iron melted. For small work it is as cheap as a coke furnace, and not
one-quarter the trouble.
The quantity of air required depends upon the gas supply. One must
be equal to the other, so that perfect combustion will take place,
and that entirely within the furnace. An excess of either gas or air
renders a high temperature an impossibility.
See that all gas taps have a large clear way through. High temperatures
and rapid working require a free supply of gas.
To adjust a new furnace to its highest power, connect both gas and air
supply with the burner. Turn on the full gas supply, light the gas, the
air-way being full open, work the foot blower and then put the gauze
nozzle of the burner tight against the hole in the casing, so that no
flame escapes around it. If the flame comes out of the lid about two
inches, the adjustment is right. If the flame is longer, open the air
check until the proper flame is obtained, or reduce the gas supply. If
smaller, or not visible, close the air check until the flame appears.
The cap-nut, which will be found at the throat of the horizontal
“mixing tube,” where the air enters and mixes with the gas, is used for
changing the size of the orifice from which the gas escapes. When the
escape is from a large orifice, a smoky, yellow, or “reducing” flame
is the result. By contracting the orifice by screwing the cap-nut on
to the gas delivery tube, a blue or oxidizing flame will be obtained.
Adjustment for the proper flame should first be made by this nut, and
the size of the flame regulated afterwards by means of a cock at the
gas main. A slightly yellow flame gives the best results when a high
heat is desired. The arrangement above described is clearly shown at
the left-hand lower corner of the sectional illustration above.
A chimney or stove-pipe 8 or 10 feet high may be used as a fixture,
and the draft partially stopped by the damper or slide when lower
temperatures are required, the gas being turned down in proportion; the
guide for the proper adjustment being that UNDER ALL CIRCUMSTANCES THE
FLAME MUST JUST COVER THE CRUCIBLE OR MUFFLE, but not extend into the
chimney so as to make it red hot. When the flame covers the crucible
or muffle, the gas is doing its extreme duty under the most favorable
circumstances, without waste.
Keep all fluxes away from the furnace jacket, as they are injurious
to fire clay, and are liable to cause the lids, etc., to stick to the
furnace.
A thin layer of quick lime on the bottom of the furnace will prevent
the crucible adhering to it when very hot.
When using a furnace for high temperatures, care should be taken not to
use a fire clay casing, as it melts at a temperature a little above
that of cast iron; plumbago or asbestos only should be used when very
high temperatures are required.
[Illustration: _Fig. 55._]
Fig. 55 represents a small gas furnace, which is extremely useful for
small meltings, experimental work, etc. It consists of a pot made of a
mixture of fire clay and asbestos, bound with rivetted iron hoops, and
having a hole in the side at which the flame enters. A lid pierced by a
central hole permits the escape of the products of combustion, and the
crucible is placed in the center so that the flame surrounds it. It is
worked with gas and a foot blower. Gas from a ⅜-inch supply pipe will
work it efficiently. About ten cubic feet of gas per hour is sufficient
for most purposes.
The casing holds the heat so perfectly that the most refractory
substances can be fused with ease, using a Fletcher foot blower. Half
a pound of cast iron requires from seven to twelve minutes for perfect
fusion; the time depending on the gas supply and pressure of air from
the foot blower. The crucible will hold about ten ounces of gold.
The power which can be obtained is far beyond what is required for most
purposes, and is limited only by the fusibility of the crucible and
casing.
[Illustration: _Fig. 56._]
Fig. 56 represents a small apparatus, which, owing to its speed and
economy of operation, has a very extended use in the jewelry and
silversmithing trades. With this apparatus a sound two-ounce ingot of
gold or silver can be moulded in two minutes. A crucible of moulded
carbon is supported by a sheet-iron slide, or plate, which is clamped
to an ingot mould by a clamp which swivels in the U-shaped cast iron
stand. The metal to be melted is placed in the crucible, and the flame
of the blow-pipe directed on it until it is perfectly fused. The whole
is then tilted over by means of the upright handle at the back of
the mould. The waste heat serves to make the ingot mould hot. No flux
should be used with the carbon crucibles. For the smaller operations,
such as making small quantities of colored golds, for electroplating
solutions, testing ingots, and the smaller operations of the jeweler
and plater, it is invaluable.
[Illustration: _Fig. 57._]
The air pressure used in operating gas furnaces varies from one to
four pounds per square inch, though the latter is seldom required
except for the severest work in large furnaces; as a general rule it
is less than two pounds in the operations of the gold and silversmith.
The pressure must be arranged so that the air supply equals that of
the gas used. This can be readily seen by the color of the flame, as
noted in instructions for handling the furnaces. For small operations
foot blowers are used. These consist of a powerful bellows having a
hemispherical pressure chamber on one side, and adapted to work either
by the hand or foot; see Fig. 57.
[Illustration: _Fig. 58._]
[Illustration: _Fig. 59._]
The perfect combustion of the gas is secured by mingling equal
quantities of gas and air in a mixing chamber, and then igniting the
mixture. In the larger furnaces this is accomplished by a mixing
chamber placed under the furnace, so as to heat the mixture before
ignition, and no pressure supply of air is necessary. In the smaller
apparatus, this mixing is done in the burner, which consists of an
inner tube carrying an air supply, surrounded by a gas tube, and the
whole surmounted by a sliding nozzle for changing the shape of the
flame. The mixing chamber being so small, the air and gas pass through
it so rapidly that considerable pressure of air must be provided to
prevent it from being excluded by the normal pressure of the gas; hence
the necessity for a blower when using small burners.
When it is not desirable to use gas, for pecuniary, or other reasons,
melting may be carried on by means of a gasoline gas flame, which is
noisy, but otherwise little inferior to coal gas. The furnaces for
gasoline differ but little in construction from the others, as will be
seen by Figs. 58 and 59. The only difference being that the burners are
applied from the side and no air pressure tubes are needed, while the
furnace is supported on legs to insure safety from fire.
[Illustration: _Fig. 60._]
The burner for gasoline is radically different from that for gas,
being, in fact, a small gas machine, Fig. 60.
In Fig. 60 _P_ is an ordinary force pump, at the bottom of which, at
_A_, is a valve which closes automatically upon releasing the pressure
from the pump, _C_ is a check valve which closes the inlet to the tank
_T_ completely; _F_ is a filling screw for introducing gasoline. _V_ is
a vent screw for letting off the pressure when through; _H_ is a pipe
leading from the tank to the burner _D_; _E_ is the burner regulator,
terminating in a fine point, closing the orifice of the burner; _S_
_S_ are packing boxes. Upon opening _C_ and pumping a few strokes
a pressure is created in the tank and on top of the fluid, forcing
it through the tubes of the burner, which being previously heated,
vaporizes the gasoline. This issues from the orifice at the end of _E_
as a highly heated gas and burns as such in the form of a powerful
blast, Fig. 61. After being once started the heat of the flame passing
through the burner, vaporizes the fluid in the tubes, and hence the
apparatus is automatic.
[Illustration: _Fig. 61._]
The air which is forced in is not consumed, so that to keep up the
blast it only requires a few strokes of the pump occasionally to
maintain the pressure lessened by the consumption of the fluid.
To operate the blow-pipe: close _E_; unscrew _F_, and introduce from
two quarts to one gallon of gasoline of 76° according to the capacity
of the tank. Replace _F_ and close _V_; open _C_ one or two turns and
give three or four full strokes of pump _P_, and close _C_. Heat the
burner by burning some of the fluid in a suitable vessel placed under
the burner; when hot enough apply a match and open _E_ gradually, until
the action is more or less uniform. If no spray or liquid issues from
the orifice, the burner is hot enough; if not hot enough, burn slowly
until no liquid or spray issues. When sufficiently heated the blast can
be made of any intensity desired, by the use of the pump as above. To
stop its action, shut the regulator _E_, or open screw _V_, or both.
When not in use the vent _V_ should invariably be kept open. The mouth
of the burner _D_, should be two or three inches from the inlet of the
furnace, or there will not be perfect combustion.
For very high temperatures and muffle work, light the burner as above
and heat the inside of the furnace to a bright red; then place the
burner against the inlet of the furnace; turn out the burner by means
of the cock _E_, and immediately turn it on again without lighting
it, when if the furnace is hot enough, the gas will ignite inside the
furnace. The heat can be regulated as in the first method of burning.
When burning inside of the furnace, there must be no flame in the
burner tube; it should all be inside the furnace, and the tube of the
burner must be close to the fire hole, or there will not be enough heat
in the tubes.
Use a drop or two of sperm oil on the piston of the pump occasionally,
also on leather washer at _F_, otherwise the apparatus will be apt to
leak, corrode and work badly.
[Illustration: _Fig. 62._]
=251.= =Muffle Furnace.= This consists of a fire-clay furnace, mounted
upon a powerful gas burner and containing an oven, also of fire-clay or
plumbago, so placed as to receive the full heat of the flame, without
permitting the direct action of the flame upon any object placed within
it. The objects are placed in and withdrawn from the muffle, or oven,
through the door shown in the cut. This door is made of two pieces so
that the upper one may be removed to watch the progress of the work
without chilling the contents of the muffle by too great an entrance
of cold air. They are extensively used for assaying, annealing, etc.,
and for many other purposes where an exact temperature is required. The
illustration shown in Fig. 62, is of a gas muffle, but they are also
made to be used with the gasoline burner previously described.
THE LATHE.
=252.= Of all the tools and machinery employed by the watchmaker, the
lathe is the most important. Very poor work is often turned out by
those possessing a first-class lathe, but there are very few persons
who can turn out good, true work, from a poor, cheap lathe, and if it
is untrue it is utterly impossible to turn out good work. Wonders can
be accomplished by the ingenious mechanic who thoroughly understands
the capabilities of the lathe. By patient skill of manipulation, the
Chinese and Japanese turn out some truly wonderful work; they succeed
in turning sphere after sphere, one inside the other, from a solid
piece of ivory, the opening from one to another being comparatively
small.
The earliest form of the lathe in the trade was the dead center: that
is, a lathe whose parts did not revolve, the object to be operated
on being placed between centers and made to revolve by means of the
bow. This form of lathe was succeeded by the live spindle or live
mandril pattern, although there were many good points about it that
must be acknowledged. It contained one great element that many modern
appliances, termed lathes, lack, i. e., the element of truth. No matter
how coarsely or crudely constructed, this truth was not eliminated,
except by the ignorance of the artisan, for the centers must remain
the same relatively, whatever may be their position in relation to the
lathe bed.
With the introduction of the live spindle lathe in this country, the
verge, Jacot and other lathes and tools of that type were rapidly
abandoned. In Europe, however, the live spindle lathe did not meet
with such a cordial reception, and it has taken many years, in some
localities, to overcome the prejudice against them; in fact, there are
still many workmen there who cling to the dead center patterns.
The all-important point in lathes of the live spindle type is
accuracy of fitting, and particularly in regard to the spindle and
its bearings, for unless a certain degree of perfection is attainable
in this particular, it is worse than useless, as it not only does not
do the work, but leads the artisan astray. The workman, sometimes,
through motives of economy, purchases foreign made lathes, that
closely resemble the American in outline and finish. These lathes,
as a usual thing, are not accurate, and in the greater majority of
cases the chucks which accompany them are worse than nothing, and yet
these lathes, in nearly all cases, are declared to be as good as the
American. There are some foreign lathes that are very carefully made,
and are quite as true as the best American, but they are the exception
and not the rule. The workman who buys one of these lathes cannot, of
course, tell whether it is right or wrong until he has placed it on his
bench and tested it, and even then he cannot be sure, for although when
a certain chuck is placed in the spindle and tested it may apparently
show no deviation from truth, there may still be untruth in the spindle
or chuck or both, as the errors in one may be counteracting the errors
in the other, and if the chuck be turned or an absolutely true chuck
placed in the spindle, the error will be made quite apparent. If an
American lathe, by any possibility, is allowed to pass the inspector,
and finds its way upon the market, the maker is only too glad to
replace it with a perfect one, for his reputation is at stake; but if
one of the imitation pattern proves untrue you will have to do the best
you can.
[Illustration: _Fig. 63._]
There are American made lathes upon the market that are as inferior in
many respects as the imitations, and the watchmaker will do well to do
without a lathe until such time as he can afford to purchase one of
known reputation. Among the first-class American lathes upon the market
may be mentioned the Webster-Whitcomb, shown in Fig. 63; the Moseley,
shown in Fig. 64; the Hopkins, shown in Fig. 65, and the Rivett, shown
in Fig. 66, and others.
An excellent lathe for the heavier work of watchmakers and jewelers,
such as cannot be performed with satisfaction on the watchmaker’s
lathe, is the No. 4 Barnes, which is shown in Fig. 67.
[Illustration: _Fig. 64._]
For screw-cutting, the manufacture of watchmaker’s tools, fishing
reels, repairs on tower clocks, in fact, all the heavier work of the
trade, it is admirably fitted.
=253.= =Care of the Lathe.= The American lathe of to-day is a marvel
of completeness in its parts, and how many hours, yea months, of study
and experiment have been bestowed upon it by its projectors and makers
to acquire these points of utility and excellency? What a vast amount
of care has been exercised for the production of a perfect lathe!
Must this care cease at the moment it passes into the hands of the
watchmaker?
It is a very easy matter at any time to wipe off the dust and oil that
may accumulate, but does this alone constitute due care? There may be a
nice glass case to cover it and keep off the dust, and a very good idea
it is, if faithfully used; but if a counter shaft is on the bench, or
much lathe work is to be done, it soon falls into blissful desuetude,
or finishes its usefulness by being broken. Then, often, a cloth is
wrapped about the lathe, which soon gets soiled and looks badly, let
alone the poor protection it affords.
[Illustration: _Fig. 65._]
Dust is omnipresent, and the greatest enemy to all active machinery;
it insidiously makes its way into every crease and crevice, and if not
promptly removed will cause untold damage. We cannot get rid of it and
must (like the industrious housewife) wage a constant warfare against
it.
The care necessary to be given to a fine lathe differs from most other
tools; it is not confined alone to the removal of dust and keeping
clean, but the fitting properly of the several parts as used. There
should be no overstraining when tightening screws, chucks, etc., or
when fitting articles in both wire and wheel chucks, and so on through
the list.
[Illustration: _Fig. 66._]
The face of the lathe bed when it comes from the makers is (or should
be) perfectly true from end to end, in order that head and tail stocks
will meet on a direct line of centers, even should they be changed
end for end, and a good lathe will meet those requirements. Now, it
is obvious to any thinking mind that if this face becomes injured by
neglect, whereby the nickeling is removed in spots or portions, they
will, in all probability, become rusty; this rust will then eat away
and throw off more, and soon the face presents an uneven surface, which
will tend to destroy the line of centers between head and tail stocks.
The head stock, usually occupying one position, causes less wear at
this point or place, while the hand-rest and tail stock are constantly
being shifted, so where there is more motion or action there must be
more wear, especially if dust, chips, or grit be allowed to accumulate
beneath them, and though the wear is seemingly imperceptible, it
nevertheless is there, and will sooner or later manifest itself, and
this is a signal that the level of the bed is becoming impaired, and,
necessarily, the truth. Thus too much care and attention cannot be
exercised in guarding against chips and dust when sliding hand-rest
back and forth on the bed.
[Illustration: _Fig. 67._]
At the end of the bed, where the tail stock takes position, many
watchmakers have the tail stock off, and this portion is more exposed
to atmospheric action, also receiving perspiration from the hands
when they come in contact. Again, others let the tail stock remain in
position, only removing when it comes in the way. In the former case,
it is well to devise some means for the protection of the bed; this is
easily done by making a sheath of chamois skin to slip tightly over
the bed; it can be removed and replaced readily, and when it becomes
soiled, can be washed.
This sheath should be fully two-thirds the length of bed, or reaching
from tail end up to hand-rest when it is close to head stock. It
preserves the bed from dampness, which is considerable in some
climates, also the perspiration of the hand and flying chips and dust.
In the second case, if the tail stock is allowed to remain on the
lathe, or, if removed and placed on the bench, it is subjected to all
the evils the bed is in the former. Our opinion is, the tail stock
should be kept in its compartment in a tight-fitting drawer, away
from dust and accidental knocks of other tools on the bench; the tail
spindle not being nickeled, is more liable to rust if left exposed, and
should be kept in a sheath of oiled paper. This may seem superfluous
and too much bother, yet it is taking proper care which tells in the
end.
The bottom of tail stock should always be brushed off before placing in
position, not only for its protection, but for fear some particle of
grit may be adhering, thereby throwing it out of truth, and screwing it
down tight only adds injury to the lathe if allowed to remain.
The head stock demands close attention; the spindle should run freely
without end-shake, and about once a week should be speeded, meanwhile
administering oil until it leaves the bearings clean, and then wiped
off. A little oil should be added every day. See that the mouth of the
spindle is kept bright and clean; thrust a piece of cloth clear through
spindle every now and then, that all dust and dirt may be removed.
Wire and wheel chucks should often be washed in gasoline to remove
gummy dirt and oil which is constantly adhering, and it is even well
each time a chuck is used, to wash off first, then wipe dry. A little
dirt on the mouth of spindle, or on the chuck, often throws it out of
truth, and consequently the article fastened therein also.
When fitting head or tail stocks, or in fact any attachment, do so
carefully. Do not bang it in place as if you held a grudge against it,
and when in position see that they are tightly screwed in place.
Having too much end-shake on live spindle, especially in soft lathes,
causes uneven wear in its bearings, besides not being reliable for true
pivoting or any such work.
When the cost of a lathe is taken into consideration, it goes to prove
that it is not easily replaced. Where is the jeweler with a stock of
goods who would retire without first seeing that his valuables were in
the safe, but how many are there that think of giving this protection
to their lathes? Some do, but the greater per cent do not. It is a good
plan to see that the head stock, the tail stock, and attachments are
in the safe and should a fire break out that endangers the store, and
no chance to save it, the feeling of satisfaction is great to know the
lathe is safe, that is, the most expensive parts, for the bed can be
purchased at a nominal cost compared to the attachments.
THE FOOT WHEEL.
[Illustration: _Fig. 68._]
=254.= In the selection of a foot-wheel the workman must be governed
by his own experience and taste, for the variety that exactly suits
one person is very distasteful to another. The swing treadle pattern
shown in Fig. 68 is a very popular one with American workmen. These
swing treadles are made in various ways by the different manufacturers,
but the methods of using them are alike. There are workmen, however,
who prefer the heel and toe motion and others that prefer the up and
down motion. This is all a matter of taste and it matters but little
what form of lathe wheel is used provided the motion is steady and the
exertion is light. As a general rule a heavy wheel, say forty pounds in
weight, will be found, on the whole, much better than a light one and
the motion will be more uniform.
=255.= =Driving Bands and Belts.= Most foot-wheels are so constructed
that either a flat or round belt may be used in transmitting the power
to the countershaft or lathe, as the case may be. Many watchmakers use
a flat belt between foot-wheel and countershaft and a round leather
belt, or cord, between countershaft and lathe. If we may judge by
appearances, this is the favorite fitting. Others use round leather
belts in both instances, while others again use cotton or hemp cord or
gut. All things considered, the round leather belt seems to possess
advantages over all others. It does not slip as easily as cotton cord,
is more elastic than gut and throws less strain on the bearings,
absorbs less power and works much smoother. The ends are fastened
together by means of an S hook and the cord may be readily tightened by
giving it an additional twist or two.
[Illustration: _Fig. 69._]
=256.= =The Countershaft.= The countershaft is indispensable in using
milling tools, wheel cutters and pivot polishers. The pattern shown in
Fig. 69 is but one of many on the market.
In some of the patterns the uprights extend through the top of the
bench and are held securely in place by means of thumb screws or wing
nuts. The pattern shown in the illustration is mounted on a solid metal
base which is intended to be fastened to the bench by means of screws.
The advantages of using a countershaft are three fold: First, you are
able to regulate your speed perfectly without changing the motion of
the foot from fast to slow or vice versa; second, your belt is carried
to the back of the bench, where it is out of the way, instead of
coming down in front of the head; and third, you obviate the necessity
of having holes in your bench on each side of the lathe, that small
articles are liable to drop through. Fig. 70 illustrates the favorite
arrangement of foot wheel, countershaft and belts.
THE BENCH.
[Illustration: _Fig. 70._]
=257.= As previously suggested (=230=) it is of the utmost importance
in doing good work, and doing it rapidly, that your bench be kept
orderly and clean at all times, and that all your tools and devices be
in their proper places, exactly where you can put your hand on them at
a moment’s notice. An excellent arrangement for a watchmaker’s bench
is shown in Fig. 70. This bench was designed by G. W. Laughlin, and
is complete in every detail. Benches can be purchased ready made from
material dealers, both with and without curtain tops, but there are
many watchmakers that prefer to make, or have made for them, a bench
varying from the usual pattern. The bench illustrated is made of black
walnut, veneered with French walnut and bird’s eye maple. The top is 21
inches wide by 41 long and is 33 inches from the floor. The drawers on
the right-hand side are 10 inches wide. In the center are two shallow
drawers, while the left-hand side is entirely boxed in.
IDLERS.
[Illustration: _Fig. 71._]
[Illustration: _Fig. 72._]
[Illustration: _Fig. 73._]
=258.= Idlers are especially valuable for use on slide rest tools,
such as pivot polishers, milling attachments, wheel cutters, etc.,
and with traverse spindle tailstocks, traverse spindle drivers, etc.,
to give a vertical direction to the belts. Idlers are constructed in
various forms, some of them being mounted on upright posts, fastened to
the bench just back of the lathe, as shown in Fig. 71; others consist
of steel rods terminating in a ball, and socket joint, where it is
fastened to the bench, as shown in Fig. 72, while in other patterns
the rod is fastened by means of a wing nut to a brace running from one
to the other of the supports of the countershaft and may be placed
at any desired angle. The idler shown in Fig. 73 can be used in this
way. Some watchmakers prefer to place their idlers on an overhead
countershaft, which is usually fastened just back of the bench and
about two and a half or three feet above it. The idler shown in Fig.
72 can be screwed to the bench or to the wall above the bench, in the
latter case it will extend out horizontally over the lathe and is out
of the way of the watchmaker when not in use. In the forms shown in
Figs 71, 72 and 73 the belt passes from the countershaft over the idler
and one long belt only is used. This style is sometimes varied by using
two separate belts one from the countershaft to the idler and another
from the idler down to the lathe. If in the latter style, a cone pulley
of rubber is used on the countershaft and also for the corresponding
pulley on the idler and a plain pulley for the down belt. Of course in
this form the idler stand must be in the form of a countershaft, as the
pulley must be fast on the shaft and the shaft itself must revolve. In
the styles shown above, the shaft is rigid and the pulleys revolve upon
it. The advantage of using the cone pulley style is that the speed of
the cutter or other attachment may be varied at will without in any way
increasing or decreasing the speed of the wheel.
CHUCKS.
[Illustration: _Fig. 74._]
[Illustration: _Fig. 75._]
[Illustration: _Fig. 76._]
[Illustration: _Fig. 77._]
[Illustration: _Fig. 78._]
[Illustration: _Fig. 79._]
=259.= True chucks are the most important adjuncts to a watchmaker’s
outfit. A true lathe with poor, untrue chucks is almost useless.
Chucks hold the work truest that comes the nearest to fitting the
holes in them. If you try to hold work in a chuck that is too large
or too small, you will soon get the chucks out of true and you will
soon become dissatisfied with your chucks, your work and your lathe.
Care should always be taken to select a chuck that will take the work
without straining it open and yet is not so large that undue pressure
will have to be used in holding it. The American split chuck, when
true, will hold almost any piece of work with the greatest precision as
regards truth; but the split chuck is a delicate attachment and will
not stand hard knocks and rough treatment. After using them, you should
clean them in benzine to remove all dirt, rinsing them in alcohol and
drying with a soft linen rag, and see that no small chips of metal are
left in the openings that may throw the work out of truth the next time
they are used. Fig. 74 illustrates the regular pattern split chucks
that accompany American lathes. Fig. 75 is a conoidal wire chuck, so
called because the shape of the mouth of the chuck is conoidal in
lieu of the shoulder usually left on wire chucks for the bend in the
spindle. Fig. 76 is an arbor chuck. This is a solid chuck on the end
of which is a threaded arbor for the reception of saws, laps, wheels,
etc., which are held firmly in position by means of the nut on the
threaded arbor. Fig. 77 is a screw chuck. This is a solid steel chuck
having a threaded hole in the end for the reception of cement brasses,
etc. Fig. 78 is a shoulder chuck. It is a split chuck with a large
opening in the end with square shoulders for the work to rest upon.
Fig. 79 is a taper chuck, which is solid and has a large opening for
the reception of tapers, centers, laps, etc. Fig. 80 is a step or wheel
chuck, which usually comes in sets of five, and as each chuck has
nine steps, a set of them will accommodate forty-five different sizes
of work. These chucks are useful for holding mainspring barrels when
fitting in the cap, should it become out of true; for trueing up the
barrel of English lever watches that are damaged by the breaking of a
mainspring and for holding almost any wheel in a watch, such as the
fitting of a center wheel to a pinion, or in making sure that hole in
the wheel is in the center. These chucks will the hold wheels from 5
to 2.25. The chucks mentioned above are the most common ones in every
day use and usually accompany the American lathe in combination sets.
As intimated, these chucks are delicate and as a usual thing they do
not receive the care they should, when their cost and the delicate
exactitude demanded of them is considered. The watchmaker who prides
himself on his good work and the orderly condition of his tools,
attachments and bench generally will purchase or make for himself a
nice chuck box with a glass or wooden cover to exclude all dust and
flying chips. You cannot expect to do good true work with a chuck that
is thrown carelessly into a drawer containing an assortment of files,
a hammer, staking block, oilstone, screw driver, sliding tongs, etc.,
and yet how many watchmakers take just this kind of care of their
chucks, and complain of their untruth, and declare that a wax chuck is
the only thing that can be absolutely relied upon for truth. Fig. 81
illustrates a neatly arranged chuck box made by the Faneuil Watch Tool
Company. In it all the various chucks may be arranged and the whole
may be covered with a glass shade to keep out all dirt. A wooden cover
might be used and perhaps would be preferable to many as it is less
liable to be broken and occupies less space and therefore admits of the
box being placed in a drawer, leaving more room on the bench for the
necessary tools and attachments.
[Illustration: _Fig. 80._]
[Illustration: _Fig. 81._]
A chuck box should be well soaked in oil so that the wood will absorb
no moisture and thus tend to rust the chucks. A small envelope made of
tissue paper and filled with quicklime will, if placed in the chuck
box, take up the moisture in the air and prevent the chucks from
rusting.
[Illustration: _Fig. 82._]
=260.= The chuck stepping device, invented and patented by Mr. Moseley,
is a valuable attachment for the lathe. In this device, shown in
Fig. 82, _a_ rests in chuck slightly less than diameter of work; _b_
tightens in rear end of draw-in spindle, and turning _c_ regulates the
depth of step. By the use of this tool any wire chuck will accurately
serve as a step chuck. It is a device of great service to the
watchmaker when used and understood. It enables him to make a step in
any wire chuck of any depth he may desire, and will push out the work
at any time when he so desires. It is very useful many times for a stop
for marking or cutting off when you want a number of pieces of the same
length or kind. Many object to the stepped chuck for general use.
[Illustration: _Fig. 83._]
=261.= In addition to the regular chucks which usually accompany
American lathe combinations may be mentioned some others which from
time to time have been placed upon the market by manufacturers of
watchmakers’ tools. These chucks were devised for holding work which it
was found in practice could not be held by the ordinary chucks.
=262.= The bezel chuck, shown in Fig. 83, was originally made with a
view of holding bezels only, but is now made so that it will hold watch
plates, coins, etc., and is adjustable to any size. It can be fitted to
any lathe and it requires but very little practice to use it, as it is
extremely simple and any one who uses a lathe can make or repair bezels
in a workmanlike manner. It holds the work as in a vise, and no amount
of turning or jarring will loosen the jaws, while it may be opened
or closed instantly by simply turning the milled nut behind the face
plate, thus enabling the operator to turn and fit a bezel perfectly, by
trying on the case as many times as necessary. It holds the bezel by
either groove, so that the recess may be turned out when too shallow or
too small for the glass, or the bezel may be inverted and turned down
when it rests too hard against the dial. It will be found especially
useful in turning out the inevitable lump of solder from the recess
of the bezel after soldering, and in fitting to case, as the process
of soldering generally makes the bezel shorter, and consequently it
will not fit the case. It also renders the operation of polishing
bezels, after soldering, the work of but a few moments. In turning out
the recess for glass in bezels, especially those of the heavy nickel
variety, it will prove a friend indeed. When, for instance, you look
through your stock of flat glasses and find none to fit, but have one
that is just too large. Any watchmaker knows that if the groove in the
bezel is imperfect, it is very apt to break the glass. This chuck is
also useful as a barrel closer, holding work while engraving, and many
other uses that will present themselves to the watchmaker.
[Illustration: _Fig. 84._]
=263.= The Hopkins’ patent adjustable chuck, shown in Fig. 84, is
designed to grip and hold firmly and accurately any size of work,
from the smallest staff to the largest pinion, watch wheels of all
sizes, mainspring barrels and other large work, and can be adjusted
to any make of lathe, by simply placing it friction tight on a plug
chuck fitted properly to the lathe. In using this chuck for staffs,
pinions, wire, etc., fasten a V-piece, 7, of proper size, in the hole
of attachment 6, taking care that both the V and the seat in which it
rests, are free from chips, dirt, etc. Then lay your work in the V and
fasten it there by means of the sliding jaw above it. This done, place
the attachment on the face of the chuck body, with the disc slipped
under the heads of the two spring bolts, and then spin the work to
center the same as when using wax. After centering thus, fasten the
disc to place by tightening the nuts on the back ends of the spring
bolts. For holding work by the web of the wheel, place the wheel under
the screw cap, on the face attachment 8, and screw the cap down firmly
on it, with the staff or pinion projecting outward through the center
hole. This done, proceed the same as when using attachment 6. For
mainspring barrels and like work, use attachment 11, and place a bit
of broken mainspring between the work and the ends of the three binding
screws, and tighten the screws down on this instead of directly on the
work.
[Illustration: _Fig. 85._]
[Illustration: _Fig. 86._]
=264.= The Spickerman patent cement chuck, shown in Figs. 85 and 86,
holds and centers accurately any wheel in a watch while drilling,
polishing or fitting new staffs or pinions, and all danger of injuring
the wheels is obviated. It will fit all kinds of American or Swiss
lathes. The holder shown in Fig. 86 at _a_, is turned down to nearly
the size of the screw for the lathe, and the screw is cut so the holder
will set as close as possible to the lathe. The face of the holder is
then turned perfectly true. Put the wheel to be centered in cap _c_, as
near to the center as convenient, and then screw on _b_. Then place the
cemented face of chuck _b_ against the face of holder _a_ on the lathe,
and with a lamp warm the cement between the surfaces, holding the chuck
by means of a pegwood against the pivot of the wheel in the cap _c_,
and it will move to an exact center as soon as warmed sufficiently. New
cement should be added occasionally between the surfaces, as the old
cement hardens and burns away, and does not center as well as when new.
Fig. 85 shows chuck with wheel inside ready for centering and drilling.
[Illustration: _Fig. 87._]
[Illustration: _Fig. 88._]
=265.= The gem patent pivoting chuck, shown in Figs. 87 and 88, is
intended as a substitute for wax when performing pivoting and like
work. By the means of the ball _b_, placed between the two sliding
sockets _c_, _c_, with the several other parts as represented in
Fig. 87, a combination of sliding and ball and socket movements, in
connection with a spring pump-center is obtained. A set of ten or more
supplementary chucks _g_, with different sizes of center holes, and
attachment _n_ for all sizes of wheels, are furnished with each chuck.
The supplementary chuck _g_, in the form of a small split chuck, is
made to fit into a hole with taper mouth, in the center of the ball
_b_, and is drawn into place and the work fastened firmly in it by
means of the binding nut _m_, which screws on to a projection extending
outward from the front of the ball. To use this chuck, proceed as
follows: Remove the nut _m_, and give freedom to the working parts by
loosening the large back nut _k_. Then to bring the hole through the
ball _b_ into line, spin the ball to center, first at the base of the
projecting screw and then at the mouth of the hole through it, and in
this position again fasten the parts, by tightening the nut _k_. Then
give freedom to the pump-center by slightly loosening the set screw
_j_. When doing this, hold your finger against the front of the chuck,
to prevent the center rod from shooting out of its place when freed.
Then having placed a supplementary chuck _g_, of proper size, in its
place in the chuck, and your work in it, with its back end resting
properly in the countersink in the end of the pump-center, fasten it
there by screwing the cap _m_ down snugly over it, using a small lever
pin when necessary for the purpose, but not with undue force. Then
again loosen the nut _k_, and spin the work to center at its outer end;
and then tighten both the nut _k_ and set screw _j_. In tightening
the set screw _j_, make sure it is so tightened as to prevent the
pump-center from slipping from place when working. If from tightening
the screw _j_, it is found that the work has been thrown in any degree
away from true center, loosen the nut _k_, leaving the pump-center
fast, and again spin to center and fasten as before. After a little
practice this can all be done in a few seconds, and the work brought to
absolute center.
In using attachment _n_, for wheels, the nut _m_ and chuck _g_ are
removed, and n is substituted therefor; the work being held on the
face of the attachment by flat-headed screws that grip the arms of the
wheel. For cylinder escape wheels a special attachment _n_ is furnished.
[Illustration: _Fig. 89._]
[Illustration: _Fig. 90._]
=266.= Fig. 89 illustrates a crown chuck, which is used for holding
crowns while undergoing repairs. The Dale chuck shown in Fig. 89
is made on the lines of the ordinary split wire chuck, a large
recess being turned in the end for the reception of the crown. The
Johanson chuck is illustrated in Fig. 90, and is quite different in
construction, a ball-shaped cap with right hand thread screwing down
onto the body of the chuck, thus holding the crown from the outside,
while a screw-center with left hand thread, holds it firmly from the
inside. This chuck is made in two patterns, one for use in a No. 40
wire chuck, as shown in Fig. 90, and the other is mounted on a regular
chuck and is ready to insert into the lathe-head the same as an
ordinary wire chuck.
THE SLIDE REST.
[Illustration: _Fig. 91._]
=267.= The slide rest is an expensive but very useful adjunct to the
lathe. It is used so extensively in this country, however, that a full
description of it seems superfluous. Fig. 91 is a fair example of a
modern slide rest for the American lathe. The tool-holder varies with
the different makers, but the rests proper are all made on the same
general principles, that of two sliding beds working at right angles
to each other, and carrying a tool-holder, capable of being raised or
lowered or set at any desired angle.
=268.= Brass is easily turned with the slide-rest in an ordinary lathe
arranged for the purpose, but the turning of steel demands more care in
setting the cutter so as to obtain the best cutting edge as well as in
determining the point of application of the tool. Preliminary trials
must be made, and the following remarks will be of service as a guide.
[Illustration: _Fig. 92._]
=269.= Engineers use a hooked tool to a very great extent for both
planing and turning. Both experience and reasoning point to the
conclusion that a tool of the form _b_ or _d_ Fig. 92, possesses many
recommendations, and numerous designs of hooked tools more or less
resembling these figures are employed with advantage; the tool occupies
the best possible position in reference to the surface it is required
to cut, and the cutting edge is both sharp and solid. It will be
evident that a certain relation exists between the cutting angle and
the point of application of the tool to the cylindrical object that
is being turned, and this it is necessary to determine. With a hooked
tool, as with the ordinary slide-rest cutter, a cutting angle which is
too acute will wear away rapidly; when too obtuse, the tool scrapes and
will only act when considerable pressure is applied.
In conclusion, it is clear that in forming or re-grinding any tool for
cutting a surface, it must be so arranged that its edge makes the least
possible angle with the surface that is consistent with the securing
of a sufficient degree of resistance to the cohesion and the hardness
of metal operated upon; in other words, the end of the tool must be
almost tangential to the circumference of the object, and the angle of
the cutting edge must be obtained by removing metal from the top face
of the tool. These principles are applicable to all tools for metals;
to the blades of drills as well as to the cutting edges of gravers, etc.
=270.= The angle of the cutting edge of the tool used in the slide rest
for steel should be less than that employed for operating on brass.
According to Holtzapffel, it may vary in the former case from 60° to
80° and, in the latter case, 70° to 90°, according as the tool is
required for rough turning or finishing. 60° and 80° may, however, be
taken as convenient angles in the cases respectively. Simple methods of
ensuring that the cutting edge has any required angle are described in
article 396.
The velocity with which the lathe revolves should also be less when
turning steel, and care must be taken that both the tool and object are
constantly moistened with oil.
It is sometimes desirable to arrange a small dropping-can for the
purpose of keeping up the supply; this may be easily done by placing
a can containing the fluid above the level of the work and allowing
a piece of lamp-wick, previously moistened, to hang from it so as to
almost touch the work: a continuous series of drops will fall, owing to
the influence of capillarity.
[Illustration: _Fig. 93._]
=271.= When roughing out work it is best that the cutter first travel
perpendicular to the object, from _a_ towards _b_, Fig. 93, and then
in the direction of the arrow. The corner _a_ should only be used for
finishing an internal angle or for roughing it out, and, in this latter
case, the cutter must advance along _a b_ and be withdrawn from the
metal in the direction of the arrow. The small face at the end, _a c_,
should be narrow.
[Illustration: _Fig. 94._]
=272.= =Forms of slide-rest cutters.= The usual forms of cutters
for use in the slide-rest are shown in Figs. 94 and 95. A and A′
are respectively the plan and side view of the most common form.
Two inclined planes _i n_ and _d c_ are formed on the left-hand and
under sides. The point on which they terminate is cut off square, a
cutting edge, which is more or less acute according to the metal to be
operated upon, being obtained by a third incline _c n_. The width of
the square cutting edge, indicated at _n_ in figure A, varies according
to the metal to be operated upon, as well as this incline _c n_. It is
advisable to be provided with at least half-a-dozen cutters of this
form, with edges of varying width and inclination, and even this number
is often found insufficient; cutters for steel should never be used in
turning brass.
[Illustration: _Fig. 95._]
A cutter may be sharpened in the usual manner for ordinary work; but
if it is desired to produce very smooth sinks, etc., one that has been
carefully polished must be used for the final cut.
The blade should cut with both its edges; the straight edge will serve
to form right-angled corners of sinks, while the other edge will form
bevels. It is hardly necessary to add that, when a square corner formed
by the first of these edges requires to be beveled by the second, the
lathe must rotate in the opposite direction and the cutter be passed
over to the opposite side of the center.
=273.= C, in the same figure, is a rounded cutter for making circular
grooves. F, Fig. 95, is for cutting the groove that receives a
barrel-cover. J and V are for forming the “tallow-drop” shoulders of
pivot-holes, etc.
It will doubtless be observed that these cutters would form nipples
that are dome-shaped and relatively somewhat high, and, for small
pivot-holes, the blade would require to be narrower and of a shape that
corresponds with the nipple it is desired to produce. L is for rounding
off angles. S is a convenient shape for smoothing the bottom of a
barrel without damage to the hook. T has a square point; it is used
narrow for cutting, for example, the passage under the escape-wheel
cock in a cylinder watch, and, when made wider, will serve to cut the
settings for jewels. In the latter case it may either be square at the
end or a little rounded at the corners.
In addition to the use indicated above, V can be employed for raising
the edge of a jewel setting.
=274.= =Sharpening slide-rest tools.= A flat surface turned in the
lathe will never be even unless the cutting face _n_ in A Fig. 94, is
smooth, and indeed polished, and its edge parallel to the face-plate.
Some care is therefore necessary in sharpening this face. The requisite
parallelism can be secured by the following method.
=275.= Sharpen the tool while it is held in the tool represented in
Fig. 96.
[Illustration: _Fig. 96._]
On a thick brass plate _l_ and parallel to its plane at one extremity
_b_, a plate _p_ is pivoted. The inclination of _p_ to _l_ can be
varied and it is fixed in any required position by the curved arc
passing under the clamping screw _j_.
A small bar _c_ is fixed to _l_ with its edge set accurately at right
angles to the line at _b′_ in which the two planes intersect. An
examination of the figure will suffice to indicate the manner in which
such a tool is used. Having set _p_ so that it makes with _l_ the angle
to be given to the cutting face, the cutter _b_ is held against the
bar _c_, where it may be fixed with a screw _v_, or in any convenient
manner, taking care to leave the portion of the cutter that is to be
removed projecting beyond the face of _p_ as shown at _b′_. Now pass
a piece of smooth oilstone or disc of steel charged with oilstone
dust over the face of _p_ until the projecting portion is removed; if
a polished face is required, this must be succeeded by a bronze or
ground glass disc charged with rouge. If the plate _p_ is of sufficient
dimensions, it will not be distorted, even though only made of hammered
brass; but it would of course be better made of steel, hardened if
possible.
=276.= If the watchmaker will make a rectangular holder to fit in his
tool post, with a square groove planed in its upper side that will fit
some particular size of tool steel, say one-fourth or three-sixteenths
of an inch, he can then buy bar steel of that size and make his cutters
by simply cutting off a piece from the bar and grinding one end to the
desired shapes and angles, thus saving a vast amount of time and labor
in the preparation of his tools, facilitating their rapid interchange
in the tool post, when working, and securing the greatest possible
rigidity of the tool, as the cutting edge projects from the holder only
far enough to allow the holder to clear the work.
GRAVERS AND OTHER HAND-TURNING TOOLS.
=277.= =Hooked gravers.= It is needless to do more than mention the
gravers that some watchmakers are in the habit of making of worn-out
files, of various forms to suit their special requirements; but we
would remind learners that care is essential in fixing the position of
the rest and the inclination that has to be given to the tool so as to
obtain a smooth surface, and at the same time a rapid removal of metal.
The most usual forms of the hooked graver are shown in Fig. 97. A will
serve to hollow out a plate, barrel, etc.; B for turning the bottom of
a barrel without touching the hook; C for forming a barrel-cover groove
after it has been roughed out with an ordinary graver. The bottom of
a barrel can also be turned with a graver of the form D held on the
=T=-rest at right angles to the bottom, and a slide-rest cutter can be
made of this form with advantage.
[Illustration: _Fig. 97._]
Some workmen incline the end cutting face of A slightly backwards from
the perpendicular to _d d_, fearing lest, in sharpening, it should
accidentally be made to incline in the other direction, and so make it
difficult to form internal square corners.
=278.= =Gravers for turning square shoulders, etc.= Very few
watchmakers are able to finish off a square shoulder by using a graver
with the usual point; as a rule, when they are smoothing the surface
of the pivot they allow the point to cut a ring in the shoulder, and
if, instead of being sharp, the point is dull, a rough groove is the
result.
To avoid such a fault it is a common practice to employ gravers with
very short faces, but their inconvenience is evident. It is much better
to retain the long lozenge-shaped face, but with the point modified, as
indicated by B or C, Fig. 98.
The ordinary point, shown at A, can be used for cutting the back
slope of a shoulder, B for forming the square-shouldered pivot, and
C for beveled shoulders. The inclination of the face _e d_ of B may
vary, the angle _e_ being more or less acute, according as more or
less use is required to be made of the point. This form of graver has
the double advantage that a pivot can be turned and smoothed at one
operation, very little polishing being needed. Moreover, the point is
less fragile, and such a graver combines the advantages of those with
pointed and square ends.
[Illustration: _Fig. 98._]
The length of this small face depends on the work required of it, thus
for making a cylinder pivot it may be about a third the length of the
pivot; this is found convenient for ensuring that the pivot shall be of
uniform diameter. The direction to be given to the face is indicated
by the dotted line _e d_, and a lozenge-shaped graver is preferable to
one of square section for this purpose. This direction _e d_ is very
important, and frequent trials should be made so as to ensure its being
always produced. The form C for beveling off a shoulder does not call
for explanation.
Although of less importance than when turning with the slide-rest, the
cutting angle of the graver should correspond with the nature of the
metal operated on. In reference to this question see article =270=.
=279.= =Spherical turning tool.= A very simple and convenient tool for
forming a sphere of metal may be made by taking a hardened steel tube
whose internal diameter is less than that of the sphere to be produced.
This is ground square and flat at one end, and sharpened by rubbing
this flat end on an oilstone. The tool is moved about over the surface
of the ball, previously roughed out, and a perfect sphere will soon be
obtained, the metal being removed by the internal edge of the tube. If
a steel tube is not accessible it will be enough to drill a hole in the
end of a softened worn-out file, subsequently hardening it.
DRILLS.
[Illustration: _Fig. 99._]
=280.= The forms ordinarily adopted for the blades of drills are shows
at A and C, Fig. 99. The form C is best suited for perforating brass
and other metals having a similar degree of hardness. The blade must
not be too thick, as, if it were, there would not be a sufficient
cutting edge. As the hardness of the metal operated on is greater, the
thickness of the blade must proportionately increase, or what amounts
to the same, the two slopes that give the cutting edges must have a
less degree of inclination. If this condition of sufficient thickness
be satisfied by a drill of the form C, it will perforate steel very
well, but its point will rapidly wear. When operating on this metal,
therefore, the form A is preferable, especially when the steel is at
all hard. Such a drill with the corners rounded off and sharpened will
last for a long time, if the cutting angles are not too acute. If the
metal is not hard, more rapid progress may be made by adopting a blade
less flattened than A, that is to say, something intermediate between A
and C.
A drill may be asserted to be good if it satisfies the following
conditions: the point must be in the middle of the blade; it must be
made of good steel that is carefully hardened, without being heated
beyond the proper temperature; lastly, it must be quite true—in other
words, in rotating it must run with sufficient truth throughout its
entire length, so that it withstands the end pressure required to cause
it to bite, and does not bend.
=281.= It must not be forgotten that: (1) if a drill is driven too
rapidly it will heat, and thus become softened as though too much
tempered; it is with a view to prevent this that, when operating upon
iron or steel, many workmen now and then dip the drill into a cold
liquid (turpentine is good for this purpose), dry it, and recommence
drilling, the hole being liberally supplied with oil; (2) when the
blade is left too hard, the cutting edge too acute, or if a feather
edge has been left by the oilstone, small hard particles that are
detached from the drill will embed themselves in the hole, and this
will be especially the case if it is worked too rapidly or with jerks;
such particles render the operation of drilling very slow and difficult.
=282.= =To drill steel of a blue temper.= At first not much difficulty
will be experienced; but when the drill reaches a certain depth and the
metal seems to oppose a gradually increasing resistance, the operation
must at once be stopped. If the blade of the drill be now examined
with a glass, it will be easy to see which points have ceased to cut,
producing instead a series of bright rings at the bottom of the hole
that are very difficult to remove. Exchange the drill for one of a
different form or, without reducing its width, change the form of the
blade; if it was arrow-headed for example, make it a semicircle, or
semi-oval, or chisel-shaped with sloping edges. All that is essential
is that the form be so changed that the bright portions of the surface
shall be gradually removed, and that no attempt be made to act on the
whole bright surface at once. Until this hard portion is removed, the
blade will require frequent sharpening.
Some authorities recommend that the hole be moistened from time to time
with dilute nitric acid, which is then washed off, and renewed when
a shiny surface is produced. Oil can with advantage be replaced by
turpentine as a lubricant for the drill blade.
The formation of hard shining surfaces is attributed to three causes:
(1) to the cutting edge being rounded, rolling as it were and hardening
the surface of the metal against which it continues to move; (2) to the
drill being made of bad steel or imperfectly hardened, so that small
particles break off and are embedded in the metal operated upon; and
(3) to a deficiency in the supply of oil, or an excessive velocity of
rotation of the drill.
These difficulties may usually be avoided by observing the following
precautions:
[Illustration: _Fig. 100._]
=283.= _Blade of the drill._ This should be neither as thin nor as
acute as is used for drilling brass. Its angle should never be less
than 100° and the incline should be at about 45°. The forms generally
employed are shown in Fig. 100, at A, B and C. At first the form A is
used, and, as the operation progresses, it is modified with an oilstone
slip.
=284.= _Drilling slowly with considerable pressure._ If the drill
rotates too rapidly or there is not sufficient oil, the surfaces of
contact will be heated and shining rings will form. It is well to
practice slightly, varying the speed of the wheel, in accordance
with the pressure applied; the speed should be more decided when the
pressure is, for the instant comparatively great. With continuous
rotation, considerable pressure should be applied with moderate
velocity. Constantly remove the drill to sharpen, clean the hole and
have an abundant supply of oil. Whatever liquid is most effective in
maintaining the drill cool will probably be the best; turpentine is
better than oil, since it has the additional advantage of increasing
the “bite” of the drill.
=285.= _The part against which the drill acts should be very rigid._
For example, if a hole is being made for a pivot in a cylinder plug
which is not provided with a shellac backing, and is, therefore,
flexible, the operation will be more tedious than when the cylinder is
filled with shellac. The firmness is usually greater when the object is
centered about the point to which the drill is applied.
=286.= _Making the drill._ The very best steel should be used, and the
precautions indicated in article =87= should be taken in the hardening.
If the steel is burnt in this process, no satisfactory results are to
be expected of it. To avoid such a danger it is often advisable to
leave the blade nearly round and thicker than is required, finishing
with a piece of oilstone. Although somewhat more tedious, this method
has the advantage of ensuring that, after hardening, all the metal
that is most liable to have been burnt is removed.
The drill must be short, the blade being thick and not much reduced at
the shoulder, in order to stand pressure when in use. A drill that has
been several times hardened is rarely good.
=287.= =Finished drills.= We would here draw the attention of
watchmakers to some beautifully made drills that have been introduced
and are known in the trade as “finished” drills, in contra-distinction
to the well known pivot drills that are always sold in the rough. They
are of two forms, corresponding to A and C, Fig. 99, for steel and
brass respectively; they are made of the best steel, carefully hardened
and tempered to the requisite degree; and a principal recommendation
consists in the fact that, while being moderate in price, they are of
definite graduated sizes, extending from 0.1 mm. to 2.5 mm. (0.004 to
0.1 inch), a range which comprises 37 distinct sizes.
=288.= =Semi-cylindrical drills.= These drills give excellent results
when driven by a wheel, and, although they have been long in use by
engineers, they are hardly known to watchmakers.
[Illustration: _Fig. 101._]
The simplest form is a cylindrical rod rounded at its end and then
filed down to a trifle less than half its thickness, as seen at _b d_
and _l i_, Fig. 101.
The length of the point is greater or less according to the nature of
the metal to be operated upon, but under no circumstances must the
point itself be sharp. With the form shown at _b d_, some of the rod
that is left cylindrical must be partially filed away; a better shape
is indicated by the dotted lines, all the metal being removed that
is outside the line _i l_. With such a drill the hole is smoothed
immediately after it is made by one or the other cutting edge of the
portion _i l_. It should be sharpened on the round, not on the flat
surface (or at any rate very slightly), because the thickness would
be rapidly reduced and the blade made smaller. When such a drill does
not turn true the back of the blade can be reduced, starting from the
cutting edge, it being observed that, with the continuous motion of the
wheel, only one edge acts. After a few trials it will be found easy to
use this form of drill.
It possesses this very great advantage: when fixed in a drill-chuck,
it can be turned exactly round, of the required diameter and finished;
so that, whenever replaced in the chuck, one can be certain beforehand
that the hole drilled will be of a definite diameter.
[Illustration: _Fig. 102._]
=289.= Fig. 102, shows, at C and D, another form of semi-cylindrical
drill; the first, C, is a front and the second a side view. The angle
_a_ is formed by a sloping semicircle and the stem of the drill is of
less diameter than the head, as indicated by the shoulder _j_. The
angle _t s r_ and the one between the face D and the plane _b a_ must
not be too acute.
This drill works evenly, but two conditions must be satisfied; it must
be maintained perfectly true by the chuck, and, in commencing, both
sides of the blade must engage against the sides of a conical opening
that forms the beginning of a hole which has to be enlarged.
[Illustration: _Fig. 103._]
=290.= At F and N M, Fig. 103, are seen front and side views of
another form of drill. While acting in a similar manner to the others
described above, it differs from them in that the blade also cuts with
its two sides; the edges, _p_, _i_, _i_, _o_, are sloped off backwards
to form cutting angles. The shape is indicated to the right of M, this
portion being the exact inverse of the side N.
As with the drills previously considered, a few trials must be made to
decide upon the best slopes for the cutting angles, etc., according to
the metal operated upon. They may be retained as left by the lathe, or
very slightly inclined, on the faces _p_ and _i_. All these forms of
drills require to be mounted so as to run very true. The point _o_ must
be accurately central. A hole that has been already drilled small can
be rapidly enlarged by such a drill as this last, the pin _o_, having
the same diameter as the one originally drilled.
[Illustration: _Fig. 104._]
=291.= =The Twist Drill.= The Morse twist drill, shown in Fig. 104, is
rapidly coming into favor with watchmakers for the heavier classes of
work, and is very desirable when drilling deeply, as this form of drill
heats slowly and the particles are carried to the surface of the work.
A large range of sizes in these drills are now carried in stock by the
material dealers.
LATHE ATTACHMENTS.
=292.= =Tailstocks.= Besides the regular tailstock which accompanies
the American lathe there are several other varieties made for use on
special kinds of work. Fig. 105 illustrates the half open tailstock
which is cut away so that the spindles can be laid in, instead of
being passed through the holes. The fixture will be found exceedingly
convenient when several spindles are to be used for drilling,
counterboring and chamfering. Fig. 106 illustrates the screw tailstock,
an attachment which is very convenient for all kinds of heavy drilling,
the spindle being moved by a screw with hand-wheel attached. Fig. 107
illustrates the traverse spindle tailstock, which will be found very
convenient for straight drilling and especially where the watchmaker
has considerable drilling to do.
[Illustration: _Fig. 105._]
[Illustration: _Fig. 106._]
[Illustration: _Fig. 107._]
[Illustration: _Fig. 108._]
=293.= =Jeweling Caliper Rest.= Although this tool was invented and
manufactured for the purpose of cutting jewel settings it may be used
to great advantage in countersinking for screw heads, opening wheels
for pinions or bushings, etc. The sliding jaws of the calipers should
be so adjusted that when the swinging part is brought back snugly
against them, the front cutting edge of the cutter in the sliding
spindle will exactly line with the center of the lathe spindle. Then
if the calipers are at the right height, when a jewel or jewel setting
is placed in the jaws of the caliper it will move the edge of the
cutter outward from the lathe center just half the diameter of the
jewel then in the caliper and the cutting made at that distance from
the center will exactly coincide with the size of the jewel to be set.
If however, when set and worked as above, it is found that the hole
cut is too large for the jewel, it will indicate that the calipers are
too low down and should be raised, provision for which is made in the
construction of the tool. Upon the other hand, if the cutting is found
too small to fit, it will indicate the calipers should be lowered. The
final cutting for the jewel seat should be made by running the center
straight inward from the face of the plate; the adjustable stop screw
on the back end of the sliding spindle, serving to gauge the depth of
the cutting.
[Illustration: _Fig. 109._]
[Illustration: _Fig. 110._]
[Illustration: _Fig. 111._]
[Illustration: _Fig. 112._]
=294.= =Pivot Polishers.= The pivot polisher is used for grinding
and polishing conical and straight pivots and shoulders. It is also
used for drilling, polishing or snailing steel wheels, milling out
odd places in plate or bridge, where only a part of a circle is to be
removed, etc. In the style shown in Fig. 109, the American Watch Tool
Co.’s polisher, and Fig. 110, the Moseley pattern, the circular base
is graduated to degrees and the fixture can be set at any angle. The
spindle has a taper hole for drill chucks, which makes the fixture very
useful for drilling either in the center or eccentric and by using the
graduations on the pulley of the headstock an accurately spaced circle
of holes may be drilled. Fig. 111 illustrates the polisher made by the
Faneuil Watch Tool Company, and is intended to be mounted on the slide
rest. Fig. 112 illustrates the Johanson pivot polisher and in general
principle is like the others. This style is made both for use on the
slide rest and also for the hand rest. When used in the latter, a
stud, shown in Fig. 113, is screwed into the base plate and supports
the tool in the hand rest, so as to be readily adjustable in any
direction. When used in the slide rest, this stud is removed and the
plate clamped between two hollow cylindrical supports by a stud which
is slipped into the groove of the slide rest and fasted by a nut at the
top, the whole forming a turret-like mount of great strength and upon
which the machine can be readily swiveled in any direction. In general,
polishers are used as follows: After the pivot is turned to proper
shape, put on your polisher, with the lap back of the pivot, usually
the cast iron lap first. A square-cornered lap for square shoulders and
a round-cornered lap for conical pivots. The laps for conical pivots
can be readily cornered with a fine file, and cross-ground with fine
oilstone to remove any lines made by graver or files. Lines on the end
can be removed the same way, or by means of the fingers often rubbing
them on a piece of ground glass which has on it a paste of oilstone
powder and oil, well mixed. Oilstone powder and oil used on the lap,
or No. 1 crocus will rough out the work well. When roughed out to your
liking, wipe off the oilstone powder or crocus and with a little oil
touch the pivot gently; repeat the second time. Then change lap for one
of boxwood or brass and use crocus No. 4, very fine, and ground down
to a paste. Proceed as with the first lap, being careful at all times
to keep the lap properly oiled and not pressed too hard against the
work, particularly in the last operation. Be sparing of your grinding
and polishing material as a little will accomplish as much work as a
large quantity and do it better. Bring the lap up carefully against the
work until spread all the way around, then proceed, bearing in mind
that grinding is not polishing, and that to polish nicely the work
and lap must be very nearly the same shape. Fig. 114 illustrates the
Hardinge pivot polisher, which is a hand polisher and much more simple
in construction and use than those mentioned above. It is attached to
the lathe bed the same as the T or hand rest. Polishing and grinding
slips are furnished with this attachment, as with the others.
[Illustration: _Fig. 113._]
[Illustration: _Fig. 114._]
=295.= =Centering Attachments or Back Rests.= These attachments are
very useful in rapidly bringing work to an accurate center, when
pivoting, staffing, etc., and particularly where a large number of
pieces have to be centered successively. Fig. 115 illustrates the
Potter patent self-centering lathe attachment which is made to fit any
pattern of American lathe.
[Illustration: _Fig. 115._]
It consists principally of the slide bed pieces _R_ and _D_, the
upright plate _A_ and the reversible anti-friction sliding jaws _O U V
X_. The upright plate _A_ is attached to the slide _D_ in such a way
that it may be readily raised or lowered, or adjusted in any other
direction at pleasure; and may be set with either side facing the
lathe-head. The sliding jaws are made of phosphor bronze anti-friction
metal and four sets, of three in a set, are furnished with each
attachment, as shown at _O_, _U_, _V_, _X_, the forms differing so
they may be adapted to the various kinds of watch work, and they are
operated in radial grooves in the upright plate _A_ by means of the
rotating lever _L_, which moves the three jaws in and out, to and from
the center, or opens and closes them in perfect unison. One set of
jaws may be withdrawn and another set substituted therefor in a few
moments. With each change of the jaws, however, the plate _A_ requires
readjustment, but this too, may be done in a few moments, as follows:
Having previously provided yourself with a bit of straight wire or a
small steel rod, turned to run perfectly true in your lathe, and having
fastened this in your chuck in the lathe, loosen the nuts _C C_, so as
to give freedom of movement to the plate _A_; then bring the attachment
to proper position on the lathe bed and fasten it there, after which
move the sliding jaws inward until they bind tightly on the piece of
straight wire held in the chuck and in this position again tighten the
nuts _C_ _C_. Once adjusted to accurate center in this way, no further
adjustment, whatever the size of the work to be operated upon, is
required, until you make another change of jaws.
In use, the end of the work to be operated upon is placed in an
accurate split chuck in the lathe, and the chuck tightened on it, just
sufficiently to hold it in place and to rotate it, the other end being
supported in the central bearing, formed by the sliding jaws. In this
position the jaws may be opened or closed as often as desired, and each
time they will bring the work to accurate center.
A similar attachment to the one above described is extensively used
by machinists and is known as the back rest. In principle it is very
similar, but is more simple in construction, and ambitious workmen can
make them without difficulty. This attachment, which is shown in Fig.
116, differs in its mode of fastening to the lathe bed and the jaws
cannot be opened and closed at one time as in the Potter attachment.
[Illustration: _Fig. 116._]
The illustration shows the rest in position on the lathe bed, looking
from the right-hand end of bed; _m_ shows the base, looking from
above, in direction of arrow _k_; _d_ shows bolt for binding it to the
lathe bed. It does not seem as though it needed much explanation, as
it will be readily seen that the head _d_ of bolt, passes up through
the longitudinal slot in the lathe bed, through the round hole in
base of back rest and is slipped back into slot _m_, when about half
a turn of nut _g_ binds it firmly to the bed. The washer _h_, on the
end of the binding screw, is riveted or soldered in place and should
be close enough to nut _g_ to allow only about half a turn to loosen
the bolt, as that is sufficient, and more space would occasion a loss
of time in running the nut back and forth to bind or loosen the rest.
It will be seen that when the nut _g_ is slackened, it binds against
the washer _h_, and it will stay there, and be just where you want it
when you are ready to use it again. The jaws are of hard brass; about
three sets, with points of different widths, will cover a large range
of work. Those shown in Fig. 116 are suitable for such work as pivoting
small French clock pinions, etc. It will be observed that the jaws are
so made that they may be changed by slightly loosening the screws. The
screw heads should have thin steel washers under them.
[Illustration: _Fig. 117._]
[Illustration: _Fig. 118._]
=296.= =Universal Head.= The universal head has entirely superseded the
clumsy universal mandrel in this country. The example shown in Fig. 117
is more accurate, less clumsy and complicated and will perform all the
work that can be performed on the universal mandrel. The face-plate
is 3½ inches in diameter, but by the use of the two crescent-shaped
slots it will hold anything in size and shape of watch work. The pump
center is operated from the back by the rubber knob and can be used
either with or without a spring. The jaws, which will pass the center,
are held in position on face of plate by springs and are fastened from
the back. Peep holes are provided in these heads in order that the
workman may examine the back of the work at all times. In the Moseley
head, shown in Fig. 117, these holes are of taper form. Fig. 118
shows a universal face-plate to be used in a chuck in the lathe. It is
smaller and less expensive than the universal head and answers very
well for some work, especially that of the lighter kind, but cannot be
recommended as highly as the universal head, as it is not so accurate.
The pump center is used to center, from the back, any object confined
in the jaws, but it sometimes becomes necessary to mount the object,
by means of wax, upon a plate, and hold the plate in the jaws. In such
a case the work must necessarily be centered from the front. This can
be done accurately by means of a piece of pegwood, as ordinarily done
on the lathe, by placing the point in the center hole and the pegwood
resting on the T-rest and observing if the free end of the pegwood
remains stationary.
=297.= =Traverse Spindle Grinder.= This tool will be found very
useful for grinding cutters, lathe centers, pump centers, reamers,
countersinks, squaring up barrel arbors after hardening, or work on any
hardened steel tool. In the hands of an ingenious workman, it will be
found exceedingly useful, as by its aid a great variety of work can be
performed that cannot be accomplished without it. Fig. 119 is intended
to be attached to the slide rest.
[Illustration: _Fig. 119._]
[Illustration: _Fig. 120._]
=298.= =Milling Fixture.= This attachment, which is shown in Fig. 120
is designed to be fitted to the slide rest and holds the wire chuck
vertically under the center of the lathe, so that articles held in the
chucks can be fed under mills or saws held in the saw arbor in the
lathe-head.
[Illustration: _Fig. 121._]
=299.= =Wheel Cutters.= The wheel cutter is a valuable addition to the
lathe. Several different styles of these attachments are made, each
possessing points of merit. They are designed for cutting all kinds of
wheels and pinions used in key and stem-wind watches. When the cutter
spindle is vertical the belt runs directly to it from the countershaft,
but when horizontal, the belt passes over idler pulleys held above the
lathe. One style of wheel-cutting attachment is shown in Fig. 121,
while another style is shown in Fig. 71.
[Illustration: _Fig. 122._]
=300.= =Rounding-up Attachment.= The Webster rounding up attachment,
shown in Fig. 122, is a very useful adjunct to the lathe. It is
attached to the top of the slide-rest. To operate, a pointed taper
chuck is put in the lathe spindle. The wheel to be rounded up is put
into the fixture and the wheel adjusted vertically so that the point of
the lathe center will be at the center of the thickness of the wheel,
after which the lower spindle of the fixture should not be moved. Now
remove the wheel, also the taper chuck, and put the saw arbor, with the
rounding-up center, in the lathe spindle, and adjust the longitudinal
slide of the slide-rest so that the rounding-up cutter will be back of
and in line with the center of the rounding-up fixture, after which the
longitudinal slide of the slide-rest should not be moved. Now put the
wheel and supporting collet in place, and proceed with the rounding-up.
MISCELLANEOUS SMALL TOOLS.
[Illustration: _Fig. 123._]
=301.= =Screw Head Sink Cutter.= This is usually made in the form of
an arbor terminating in a cutting edge similar to the rose-cutter,
but having a projecting pin from its center. This tool will be found
especially useful in replacing broken end-stones. The jewel being set
in brass, is held by two screws, on opposite sides, the screw heads
being let in or sunk even with the surface, half of the screw head
projecting over on the end-stone. The end-stones furnished by the watch
companies are not sunk for these screw heads, but are round and of the
proper diameter. These cutters will cut away from the jewel setting the
space to be occupied by the screw head in a very few moments and in a
very perfect manner. All of the watch companies do not use the same
diameter of screw head in the cock and potance, consequently you will
be compelled to make separate tools for the different makes of watches.
With a set of five or six of these cutters you can fit any American
watch. After you have completed your set, of say five or six cutters,
select a small brass plate and bore five or six small holes in a row,
in which the guide pins of the cutters will enter, and then cut with
the tools a number of sinks, numbering these holes in the plate and
also the arbors of the tools with corresponding numbers. You will then
have a plate similar to Fig. 123 which can then be used as a gauge for
measuring the heads of screws.
[Illustration: _Fig. 124._]
These cutters are easily made as follows: cut off a piece of wire of
the required diameter, about one inch long, and place it in a chuck
that fits it snugly and turn one end to a center, about 40°; now
reverse the wire in the chuck and be sure it is true; select a drill
that will pass through the screw hole in the cock or potance freely
and proceed to drill a hole in the center of the end of the wire, about
¹⁄₁₆ of an inch deep. Remove from the lathe and with a sharp file and
graver, proceed to cut a series of teeth as equal and even as possible.
Use a good strong glass while working and be sure you have every tooth
sharp and perfect, as upon this depends the quick and nice work you
expect from the tool. When this is well done, proceed to temper fairly
hard and polish up the outside to make it look workmanlike. Now select
a piece of steel pivot wire, of a size that will almost fit in the hole
drilled in the end of the tool and polish down to the proper size to
drive in the hole tightly. Allow the wire to project about ¹⁄₁₆ of an
inch, taper the point and polish. The tool is now complete and will
resemble Fig. 124. Select an end-stone of a diameter to fit tightly in
the cock or potance, as maybe required; set the hole jewel in place and
then the end-stone pressed down tightly against the hole jewel. Place
your cutter in a chuck that fits it true; select a smaller medium sized
drill rest and place it in the tail stock spindle. Hold the cock, or
potance, with the jewels in place, against the drill rest, level, and
proceeding to run the lathe at a fair speed, slowly feed the cock or
potance to the cutter, the projecting pivot in the end of the cutter
passing through the screw hole and acting as a guide to keep the cutter
in the center of the hole. Caution must be exercised, or you will cut
the recess for the screw heads too deep, as these little cutters are
very deceiving and cut much faster than you would suppose. In fitting
an end-stone, select one that is more than flush when the jewel hole
and end-stone are in the proper position, and after sinking the screw
head as described, turn off on the lathe almost flush or level. Make a
small dot on one side of the end-stone as a mark or guide in replacing
it. Remove the end-stone and proceed to polish the top of the setting
on a plate glass polisher.
=302.= =Screw Extractors.= The Bullock Screw Extractor, shown in Fig.
125, is a simple yet very valuable tool to the watchmaker who finds he
has a plate in which a screw has been broken off. To use this tool,
first fasten it in your vise, then bring one end of the broken or
rusted-in screw against screw center and the broken screw head against
screw driver; turn the washers so as to hold the broken screw firmly in
place; turn the plate gently and the broken screw will follow the screw
driver point out of the plate. It may be necessary in some instances to
turn the screw driver point against the broken head with a good deal of
force in order to start the screw. A little benzine or kerosene applied
to the screw will help to loosen it.
[Illustration: _Fig. 125._]
The ingenious workman can, with the expenditure of a little time, make
an attachment for removing broken screws, somewhat similar to the
above. Take two common steel watch keys having hardened and tempered
pipes—size, four or five—having care that the squares in each are of
the same size and of good depth. Cut off the pipes about half an inch
from the end; file up one of these for about one-half its length, on
three equal sides, to fit one of the large split chucks of the lathe.
Drill a hole in one of the brass centers of the lathe of sufficient
size and depth, into which insert the other key-pipe, and fasten with
a little solder. Soften a piece of Stubbs’ wire, to work easily in the
lathe, and turn down for an eighth of an inch from the end to a size
a little smaller than the broken screw in the plate; finish with a
conical shoulder, for greater strength, and cross-file the end with a
fine slot or knife-edge file, that the tool may not slip on the end of
the broken screw; cut off the wire a half inch from the end and file
down to a square that will fit closely in one of the key-pipes. Make
a second point like the first one and fit it to the other key-pipe;
harden in oil, polish, and temper to a dark straw color. Fit the brass
center into the tail stock. To use, put the tools in place in the
lathe, place the broken end of the screw against the end of the point
in the lathe-head; slide up the back center and fasten the point firmly
against the other end of the screw, that it may not slip or turn;
revolve the plate slowly, and the broken screw, being held fast between
the two points will be quickly removed. To remove a broken pillar
screw, place the broken screw against the point in the lathe-head,
holding the plate firmly with the right-hand, the pillar on a line
with the lathe center; turn the lathe-head slowly backward with the
left-hand, and the screw will be removed. Should the tool slip on the
broken screw, and fail to draw it out, drill a hole in the lower or
dial side of pillar, down to the screw point (if the size of the pillar
will admit of it), and with the second point in the back center, remove
the screw in the same manner as in the first process. Five or six sizes
of these points will be found sufficient for the majority of these
breakages that may occur.
It sometimes happens that a screw gets broken off in a watch plate in
such a manner that it is impossible to remove it with tools without
marring the plate. In such an event proceed as follows: Put enough
rain water in a glass tumbler to thoroughly cover the plate and add
sulphuric acid, until the water tastes a little sharp. Place the plate
in the solution and allow it to remain a few hours, when the screw
will partially dissolve and drop out. Remove from the solution, wash
thoroughly in clean water, then in alcohol and dry in saw dust. The
solution will not injure the brass plate or gilding in the slightest,
but care must be taken to remove all other screws or cemented jewels,
previous to immersion.
[Illustration: _Fig. 126._]
=303.= =Roller Remover.= There are numerous designs in the way of
roller removers upon the market, some of them good but many of them
weak and liable to bend where the roller is very tight on the staff.
All points being considered, the Hardinge remover, shown in Fig. 126,
is perhaps the strongest and best on the market and is built on true
mechanical principles.
The nose in the center and top of the illustration is drilled up so as
to receive a balance pivot without bearing on its point, and can be
moved towards or from the two bent prongs by means of the thumb nut
at the bottom of the tool. The prongs can be spread apart or drawn
together, and are secured in place by means of the binding screws at
the sides. In using the remover the feet of the two prongs are brought
under the roller and secured by the binding screws. The nose is now
advanced against the shoulder of the bottom pivot and the staff can be
driven out without damage to either roller or staff.
[Illustration: _Fig. 127._]
=304.= =Balance Protectors.= These are of two kinds and for entirely
different operations. The Arrick protector, shown in Fig. 127, is used
for protecting balances while working upon the pivots while in the
lathe. No matter how careful a person may be, accidents will happen,
and the least accident to a compensation balance gives the workman
considerable trouble. The least slip of the graver, polisher or hand
rest and great damage is the result. The staff is passed through the
hole in the protector, and held in a wire chuck, and the protector
is secured to the arms of the balance by two screws. The Bullock
protector, shown in Fig. 128, is designed to protect the balance and
other wheels from heat while drawing the temper from staff or pinion
for the purpose of pivoting.
[Illustration: _Fig. 128._]
[Illustration: _Fig. 129._]
=305.= =Beat Block.= This simple device obviates the necessity of
marking the balance to see that it is in beat. Before taking off the
hair spring lay it on the block, shown in Fig. 129, turn the balance so
the roller pin hits on the side the arrow points, then turn the table
so that the line comes under the stud. In replacing the balance put the
stud over the line and it will then beat the same as before. By using
this tool you also avoid getting the balance out of true.
=306.= =Female Centers.= Centers are of two kinds,, male and female.
The ordinary centers that accompany the lathe, which are male centers,
are familiar to all watchmakers. Female centers, however, are not so
well known among watchmakers, and they can be used to great advantage
in many operations where other and less simple attachments and means
are usually resorted to. You should have at least six pairs of female
centers, the largest being one-fourth of an inch in diameter, which
will accommodate as large a piece as you will wish to handle on your
watch lathe, viz: winding arbors for clocks. These female centers are
made from steel tapers, the same as male centers are made, but instead
of turning the end to a sharp point they are countersunk, Fig. 130.
First place the taper in a chuck and turn off the outside and end true;
drill a small hole in the center of the taper, while the lathe is
running, and deep enough so the countersink will not reach the bottom
of the hole, or one-eighth of an inch deeper than the countersink.
Harden the end only, and after tempering polish off the bluing. After
you have made all the sizes you require, test all of them in your lathe
to make sure they did not get out of true in tempering.
[Illustration: _Fig. 130._]
These female centers are very useful for holding or suspending any
article in the lathe that is too large to be held in the split chucks.
Pivots of clocks can be turned and polished very quickly and accurately
in these centers.
Almost any kind of large work can be done on a medium sized
watchmaker’s lathe by fitting to it a face plate one and three-fourths
inches in diameter, with four slots, and fitted to a chuck with
a standard taper hole to receive both male and female centers
interchangeably. With two styles of dogs, almost any kind of large
clock work can be readily handled.
These centers prove very useful for many odd jobs. As an example: It is
a very common occurrence to hear an American clock beat irregularly,
caused by the escape wheel being out of round. Select a pair of female
centers that will admit the ends of the pivots of the escape wheel
snugly; place one center in the taper chuck and the other in the tail
stock spindle, and suspend the escape pinion in these centers; fasten
on a dog, run the lathe at a high speed and hold a fine sharp file so
it will touch the teeth of the ’scape wheel slightly, and in a moment
the wheel will be perfectly round, after which sharpen up the teeth
that are too thick.
[Illustration: _Fig. 131._]
=307.= =Drill Rest.= In using the lathe for drilling, a great saving
in both time and drills can be effected by using a drill rest similar
to that shown in Fig. 131. It is well to have a half dozen different
sizes, starting at ¼ inch and increasing by ⅛ inch, for various classes
of work. These rests are not kept by material dealers, but can be
made by the watchmaker. Saw from a piece of rolled sheet brass, say
1-16 inch thick, the circles required, leaving metal enough to finish
nicely. Place a steel taper plug in the taper chuck of your lathe and
turn down a recess, leaving a shoulder on the taper. Drill a hole
through the brass plate to fit the steel taper tightly. Place the end
of the taper on a lead block and proceed to rivet the brass plate,
on the taper, making sure that it is true replace the taper in the
lathe chuck and proceed to turn the face and edge of the brass plate
perfectly true and to the proper size. Those who have tried to drill
a straight hole through an object by holding it in the fingers know
just how difficult it is to do, but by placing one of these drill rests
in the spindle of the tail stock, placing the article to be drilled
against it and bringing it up against the drill, you can drill the hole
perfectly upright and avoid all danger of breaking the drill.
[Illustration: _Fig. 132._]
=308.= =Filing Fixture or Rest.= These rests will be found very
convenient in squaring winding arbors, center squares, etc. There are
several makes of these tools, but they are all built upon the same
principle, that of two hardened steel rollers on which the file rests,
and Fig. 132 is a fair example. One pattern is made to fit in the hand
rest after the =T= is removed, while the other is attached to the bed
of the lathe in the same manner as the slide rest. The piece to be
squared is held in the split or spring chuck in the lathe, and the
index on the pulley is used to divide the square correctly. Any article
can be filed to a perfect square, hexagon or octagon as may be desired.
The arm carrying the rollers can be raised or lowered as required for
adjustment to work of various sizes.
=309.= =Filing Block.= A contrivance made to take the place of the
filing rest, which was made of box wood or bone. Ide’s filing fixture,
shown in Fig. 133, consists of a cylinder of hardened steel, riveted
upon a staff which in turn enters a split socket. The surface of
the steel cylinder is grooved with various sizes of grooves for the
different sizes of wire, or to suit any work.
[Illustration: _Fig. 133._]
[Illustration: _Fig. 134._]
Fig. 134 illustrates Melotte’s revolving bench block, which combines
both anvil and filing block. No. 1 is a steel anvil which may be
instantly revolved and stopped on quarters. No. 2 is a rubber block,
held by friction on its arm, and can readily be turned to any position.
This rubber, being slightly elastic, makes a very suitable filing bed
for small articles of any material and may be used without risk of
scratching or defacing polished surfaces. No. 3 is a wooden block, held
on to its arm by a spring friction device, which also allows it to be
turned around to any desired position. The three-armed hub is revolved
by pulling out slightly and is automatically held perfectly firm and
solid in any of the three positions.
[Illustration: _Fig. 135._]
=310.= =Micrometer Caliper.= Fig. 135 is a full size cut of the Brown &
Sharp Mfg. Co.’s micrometer caliper. It measures from one-thousandth of
an inch to one-half inch. It is graduated to read to thousandths of an
inch, but one-half and one-quarter thousandths are readily estimated.
This instrument is also graduated to the hundredths of a millimeter,
but when so graduated the table of decimal equivalents is omitted.
They are also made to read to ten thousandths of an inch. The edges of
the measuring surfaces are not beveled, but are left square, as it is
more convenient for measuring certain classes of work. It will gauge
under a shoulder or measure a small projection on a plain surface.
Watchmakers will especially appreciate micrometers of this form. This
tool will be found very useful for gauging mainsprings, pinions, etc.
In the caliper, shown by cut, the gauge or measuring screw is cut on
the concealed part of the spindle C, and moves in the thread tapped in
the hub A; the hollow sleeve, or thimble D is attached to the spindle
C and covers and protects the gauge screw. By turning the thimble, the
screw is drawn back and the caliper opened.
The pitch of the screw is 40 to the inch. The graduation of the
hub A, in a line parallel to the axis of the screw, is 40 to the
inch, and is figured 0, 1, 2, etc., every fourth division. As the
graduation conforms to the pitch of the screw, each division equals the
longitudinal distance traversed by the screw in one complete rotation,
and shows that the caliper has been opened 1-40th or .025 of an inch.
The beveled edge of the thimble D is graduated into 25 equal parts,
and figured every fifth division 0, 5, 10, 15, 20. Each division when
passing the line of graduation on hub A, indicates that the screw has
made 1-25th of a turn, and the opening of the caliper increased 1-25th
of 1-40th, or a thousandth of an inch.
Hence, to read the caliper, multiply the number of divisions visible
on the scale of the hub by 25, and add the number of divisions on the
scale of the thimble, from zero to the line coincident with the line
of graduation on hub. For example: As the caliper is set in the cut,
there are three whole divisions visible on the hub. Multiply this
number by 25, and add the number of divisions registered on the scale
of the thimble, which is 0 in this case, the result is seventy-five
thousandths of an inch. (3 × 25 = 75 0 = 75). These calculations are
readily made mentally.
Differences between Wire Gauges in Decimal Parts of an Inch.
Key:
A - No. of Wire Gauge.
B - American or Brown & Sharpe.
C - Birmingham or Stubs’.
D - Washburn & Moen Manufacturing Co., Worcester, Mass.
E - Trenton Iron Co., Trenton, N.J.
F - New British.
G - Old English from Brass Mfrs. List.
H - No. of Wire.
==================================================================
A | B | C | D | E | F | G | H
-------+---------+------+-------+--------+-------+--------+-------
000000 | ---- | ---- | .46 | ---- | ---- | ---- | 000000
00000 | ---- | ---- | .43 | .45 | ---- | ---- | 00000
0000 | .46 | .454 | .393 | .4 | .4 | ---- | 0000
000 | .40964 | .425 | .362 | .36 | .372 | ---- | 000
00 | .3648 | .38 | .331 | .33 | .348 | ---- | 00
0 | .32495 | .34 | .307 | .305 | .324 | ---- | 0
1 | .2893 | .3 | .283 | .285 | .3 | ---- | 1
2 | .25763 | .284 | .263 | .265 | .276 | ---- | 2
3 | .22942 | .259 | .244 | .245 | .252 | ---- | 3
4 | .20431 | .238 | .225 | .225 | .232 | ---- | 4
5 | .18194 | .22 | .207 | .205 | .212 | ---- | 5
6 | .16202 | .203 | .192 | .19 | .192 | ---- | 6
7 | .14428 | .18 | .177 | .175 | .176 | ---- | 7
8 | .12849 | .165 | .162 | .16 | .16 | ---- | 8
9 | .11443 | .148 | .148 | .145 | .144 | ---- | 9
10 | .10189 | .134 | .135 | .13 | .128 | ---- | 10
11 | .090742 | .12 | .12 | .1175 | .116 | ---- | 11
12 | .080808 | .109 | .105 | .105 | .104 | ---- | 12
13 | .071961 | .095 | .092 | .0925 | .092 | ---- | 13
14 | .064084 | .083 | .08 | .08 | .08 | .083 | 14
15 | .057068 | .072 | .072 | .07 | .072 | .072 | 15
16 | .05082 | .065 | .063 | .061 | .064 | .065 | 16
17 | .045257 | .058 | .054 | .0525 | .056 | .058 | 17
18 | .040803 | .049 | .047 | .045 | .048 | .049 | 18
19 | .03539 | .042 | .041 | .039 | .04 | .04 | 19
20 | .031961 | .035 | .035 | .034 | .036 | .035 | 20
21 | .028462 | .032 | .032 | .03 | .032 | .0315 | 21
22 | .025347 | .028 | .028 | .27 | .028 | .0295 | 22
23 | .022571 | .025 | .025 | .024 | .024 | .027 | 23
24 | .0201 | .022 | .023 | .0215 | .022 | .025 | 24
25 | .0179 | .02 | .02 | .019 | .02 | .023 | 25
26 | .01594 | .018 | .018 | .018 | .018 | .0205 | 26
27 | .014195 | .016 | .017 | .017 | .0164 | .01875 | 27
28 | .012641 | .014 | .016 | .016 | .0148 | .0165 | 28
29 | .011257 | .013 | .015 | .015 | .0136 | .0155 | 29
30 | .010025 | .012 | .014 | .014 | .0124 | .01375 | 30
31 | .008928 | .01 | .0135 | .013 | .0116 | .01225 | 31
32 | .00795 | .009 | .013 | .012 | .0108 | .01125 | 32
33 | .00708 | .008 | .011 | .011 | .01 | .01025 | 33
34 | .006304 | .007 | .01 | .01 | .0092 | .0095 | 34
35 | .005614 | .005 | .0095 | .009 | .0084 | .009 | 35
36 | .005 | .004 | .009 | .008 | .0076 | .0075 | 36
37 | .004453 | ---- | .0085 | .00725 | .0068 | .0065 | 37
38 | .003965 | ---- | .008 | .0065 | .006 | .00575 | 38
39 | .003531 | ---- | .0075 | .00575 | .0052 | .005 | 39
40 | .003144 | ---- | .007 | .005 | .0048 | .0045 | 40
-------+---------+------+-------+--------+-------+--------+-------
[Illustration: _Fig. 136._]
=311.= =Registering Gauge.= The registering gauges shown in the
illustrations are two of the best examples of this class of tools. They
are manufactured by A. J. Logan, Waltham, Mass., and are very accurate
and nicely finished. Fig. 136 is an upright and jaw gauge, and Fig.
137 is designed as a jaw and depth gauge. They are both made to gauge
one-thousandth of a centimeter or one-thousandth of an inch. Fig. 137
shows the piece of work marked A being gauged, while B represents a
sliding spindle to get the depth of a hole or recess, or the thickness
of any piece of work, which will be indicated on the dial.
[Illustration: _Fig. 137._]
[Illustration: _Fig. 138._]
[Illustration: _Fig. 139._]
Another form of registering gauge is shown in Fig. 138. It is an
English gauge and but little used in this country. The principle of its
construction, however, is good, and any ingenious watchmaker can make
it. The back of the dial is recessed and arranged as in Fig. 139. One
limb is fixed; the other is pivoted, and has a few rack teeth meshing
into a center pinion. The pinion carries the hand, which should make a
revolution in closing the calipers. The spiral spring attached to the
pinion is to keep it and the hand banked in one direction for shake.
The spring _s_ is to keep the jaws open. The milled headed screw and
the clamp _c_ are to fix the jaws in case it is required to do so.
A cover is snapped into the recess, and takes the back pivot of the
pinion.
[Illustration: _Fig. 140._]
=312.= =Staff Gauge.= The tool shown in Fig. 140 is designed for
measuring the height of the balance staff from the balance seat to
the end of the top pivot. The illustration is enlarged to give more
distinctness. _E E′_ is a piece of curved steel about ¹⁄₂₀ of an inch
thick, and ¹⁄₂₅ of an inch wide. On the lower side from _E′_ to the
end, the arm is filed down in width and thickness to correspond to an
ordinary balance arm; _C_ is a slot in the upper arm _E_, which allows
_A_, _B_, _D_, _A′_ to be moved backward and forward. _D D′_ is a round
brass post drilled and tapped. The part _D′_ has a thread cut on it,
and the part shown in the slot _C_ fits with easy friction. _B_ is a
lock-nut, drilled and tapped to fit the thread on _D′_. It is for the
purpose of clamping _D D′_ against the arm _E_. _A A′_ is a small steel
screw with milled head, and is made to fit the tapped hole in _D D′_.
Mr. Beeton describes his method of using this tool as follows: Take
your measurement of the distance _the balance seat is to be from
the end of the top pivot_, as follows: remove the end-stone in
balance-cock, and screw the cock on the top of the top plate (18-size
full plate movement); then taking the plate in your left-hand, and
tool (shown in Fig. 139) in your right, place _H_ in position, so that
the end of the screw _A′_ rests on the jewel in the balance cock, and
notice the position of the arm _E′_ which corresponds to the balance
arm, between the top plate and under side of the balance-cock. If the
distance between the arm _E′_ and end of screw _A′_ is too great,
the arm _E′_ will be too low and touch the plate; if not enough, it
will be too high and touch the regulator pins. Therefore, all that is
necessary to do is to move the screw _A A′_ up or down as the case may
be, sufficiently to ensure that the arm _E′_ will assume the position
the _arm of the balance_ is to have. Take an 18-size balance with
oversprung hairspring, the arm is at the bottom of the rim; in that
case, when measuring, the screw _A′_ is adjusted so as to bring the
arm _E′_ close to the plate, when _A′_ is resting on the balance jewel;
if the balance is old style with undersprung hairspring, the balance
arm is at top of rim, in which case _A′_ is adjusted so that the arm
_E′_ is close to the balance cock; if the balance arm is in the center
of the rim, as in some English and Swiss balances, the screw _A′_ is
adjusted so that the arm _E′_ is midway between the plate and cock.
The reason the part _A_, _B_, _D_, _A′_ are arranged to move laterally
in slot _C_ is, because all balance shoulders are not the same distance
from the center, and where, in some cases, the screw _A′_ would be in a
line with the center of the staff when the arm _E′_ was resting on the
balance seat, in other cases it would reach past the center, of course,
short of it; and, therefore, it is made adjustable to suit all cases.
[Illustration: _Fig. 141._]
=313.= =Staff or Cylinder Height Gauge.= The obvious advantage of this
tool, which is shown at Fig. 141, is the automatic transfer of the
measurement so that it may be readily applied to the work in hand. The
tool, as the illustration shows, consists of a brass tube terminating
in a cone-shaped piece. To the bottom of this cone is attached a disc
through which a needle plays. Around the upper end of the tube is a
collar upon which is fixed a curved steel index finger. A similar jaw,
which is free to move, works in a slot in the tube. The movable jaw
is tapped and is propelled by a screw that terminates in the needle
point. This tool is very useful in making the necessary measurements
required in putting in a staff. To use it in this work, set the pivots
of the gauge through the foot hole, and upon the end-stone project the
needle such a distance as you wish the shoulder to be formed above the
point of the pivot. Next set the gauge in the foot hole as before, and
elevate the disc to a height that shall be right for the roller, which
is done by having the lever in place, the little disc showing exactly
where the roller should come. Finish the staff up to that point; then
take the next measurement from the end-stone to where the shoulder
should be, for the balance to rest upon. This point being marked,
the staff can be reversed and measurements commenced from the upper
end-stone, by which to finish the upper end of the staff. Distances
between the shoulders for pinions and arbors can be obtained with the
same facility, a little practice being the only requisite.
=314.= =Vernier Caliper.= Fig. 142 is an illustration of the Vernier
Caliper, a light, convenient and valuable instrument for obtaining
correct measurements. The side represented in the illustration is
graduated upon the bar to inches and fiftieths of an inch, and by the
aid of a Vernier is read to the thousandths of an inch (see description
below). The opposite side is graduated to inches and sixty-fourths of
an inch. The outside of the jaws are of suitable form for taking inside
measurements, and when the jaws are closed, measure two hundred and
fifty thousandths of an inch in diameter.
[Illustration: _Fig. 142._]
These instruments can be furnished with millimeters (in the place of
sixty-fourths of an inch), and provided with a Vernier to read to
one-fiftieth of a millimeter.
On the bar of the instrument is a line of inches numbered 1, 2, 3,
each inch being divided into tenths, and each tenth into five parts,
making fifty divisions to one inch. Upon the sliding jaw is a line
of divisions (called a Vernier, from the inventor’s name), of twenty
parts, figured 0, 5, 10, 15, 20. These twenty divisions on the Vernier
correspond to extreme length with nineteen parts, or nineteen-fiftieths
on the bar, consequently each division on the Vernier is smaller than
each division on the bar by one-thousandth of an inch. If the sliding
jaw of the caliper is pushed up to the other, so that the line 0 on
the Vernier corresponds with 0 on the bar, then the next two lines on
the left will differ from each other one-thousandth of an inch, and
so the difference will continue to increase one-thousandth of an inch
for each division till they again correspond on the twentieth line on
the Vernier. To read the distance the caliper may be open, commence by
noticing how many inches, tenths and parts of tenths the zero point on
the Vernier has been moved from the zero point on the bar. Then count
upon the Vernier the number of divisions until one is found which
coincides with one on the bar, which will be the number of thousandths
to be added to the distance read off on the bar. The best way of
expressing the value of the divisions on the bar is to call the tenths
one hundred thousandths (.100) and the fifths of tenths, or fiftieths,
twenty thousands (.020). Referring to the accompanying cut, it will
be seen that the jaws are open one-tenth of an inch, which is equal
to one hundred thousandths (.100). Suppose now, the sliding jaw was
moved to the left, so that the first line on the Vernier would coincide
with the next line on the bar, this would then make twenty thousandths
(.020) more to be added to one hundred thousandths (.100), making the
jaws then open one hundred and twenty thousandths (.120) of an inch. If
but half the last described movement was made, the _tenth line on the
Vernier_ would coincide with a line on the bar, and would then read,
one hundred and ten thousandths (.110) of an inch.
[Illustration: _Fig. 143._]
=315.= =Hair Spring Stud Index.= Fig. 143 illustrates Johanson’s hair
spring stud index. The engraving shows the full size of the tool, which
consists of a steel plate mounted on feet, and pierced with a number
of holes for the reception of screws, when taking down a watch. In the
center of the index is a hole for the staff, and an oblong slot for the
reception of the roller jewel. To get any American movement in beat,
proceed as follows: In front of No. 100 is a small spring; push same
towards No. 10; then place the balance on top of the stand, with staff
in center and roller jewel in the oblong hole; let the spring back
gently; the balance will then take its own position. Set degree hand
in front of the desired degree, as per direction on index table; place
hair spring stud in front of degree hand, and push on the collet.
INDEX TABLE FOR HAIR SPRING STUDS.
_Size._ _Degree._
Columbus 18 Open Face Breguet 23
Columbus 6 Open Face Breguet
Elgin 18 Open Face Breguet 66
Elgin 16 Open Face Breguet 52
Elgin 16 Flat Hair Spring 52
Elgin 10 Flat Hair Spring 50
Elgin 6 and 8 Flat Hair Spring 50
Elgin 0 Flat Hair Spring
Illinois 18 Open Face Breguet 33
Illinois 18 Hunting 84
Illinois 18 Open Face Flat 89
Illinois 16
Illinois 6 Hunting 52
Illinois 4
Hampden 18 Dueber Hunting 80
Hampden 18 Open Face 75
Hampden 16
Hampden 6 Hunting 50
Howard 18 Old Model 5
Howard 18 New Model 23
Howard 16
Howard 6
Rockford 18 27
Rockford 6
Waltham 18 Key Flat Hair Spr’g 48
Waltham 18 O. F. Hair Spring 61
Waltham 18 Breguet 50
Waltham 14-16 42
Waltham 4-6 50
Waltham 1 42
Seth Thomas 18 Open Face 50
Seth Thomas 18 Hunting 52
=316.= =Oil-cup Drills or Chamfering Tools.= The reservoirs that
contain a supply of oil at the ends of pivot holes are made in the
lathe with a semi-cylindrical drill, or by hand with a chamfering tool
of the form shown at B or C, Fig. 144. A drill gives a clean cut, but
necessitates a subsequent polishing of the hole; as to the chamfering
tool here referred to, some inconvenience will be experienced in its
use, owing to the point being apt to jump out of the hole and make
irregular scratches on the brass, which are difficult to remove.
[Illustration: _Fig. 144._]
[Illustration: _Fig. 145._]
The best shapes of drills for making, or at any rate for re-forming or
finishing oil-cups, are shown at D and F, Fig. 144, and in Fig. 145.
D and F are two drill-blades that terminate in non-cutting circular
arcs. The flat curved end is more and more inclined from the top
towards the corner, from _i_ towards the side _e_; the angle at _i_
becoming more acute, and at _e_ more obtuse towards the corners. The
drill will, of course, only cut when rotating in one direction; in the
other direction the obtuse angles and the reverse sides of the cutting
angles will act as burnishers. Thus if the angles on either side are
well formed and the blade has been polished, the surface of the oil-cup
will be clean cut and polished. F is similar to D, but made from a
steel rod.
=317.= _Observations on making the oil-cups._ Reservoirs that are made
with a drill, or with a chamfering tool by hand, will often be found
to be eccentric, and, when a pivot-hole is bushed and re-drilled,
it proves to be struck from a different center from the oil-cup. In
such cases watchmakers often give themselves endless trouble without
securing a cup of good form and well centered. This difficulty can be
avoided by using the tool in a lathe driven by a wheel; then, holding
the plate in one hand square against a drill rest in tail stock,
advance the tail stock with the other hand so as to bring the plate in
contact with the drill.
When it is only required to correct the form of an oil-cup, the drill
may be replaced by a rod with file cuts on its rounded extremity (H,
Fig. 144). The reader will find no difficulty in making such a cutter
for himself, drawing a file with both hands over the rounded end, but
always in the direction of the file-cuts. After covering the surface
with lines in this manner, rotate the cutter through a right angle and
form a number of cross cuts. Or roughen the surface with a chisel of
the form shown at H; after making a few cuts parallel to each other,
turn the chisel through an angle and repeat the operation.
=318.= =Chamfering Tool.= As is well known, this is used for removing
the roughness that a drill leaves at the edge of a hole, or to take off
the cutting edge around a screw head sink, etc., thus forming a bevel
edge. The tool commonly has a flat semicircular blade, the diameter of
which depends on size of hole to be made; this semicircle is ground to
a cutting edge like a drill, as shown at A, Fig. 144. Chamfering tools
are also made pyramidal, with flat faces, as at B and C; the angle
at the apex is more or less acute, according to the depth of chamfer
required.
The oil-cup drills D and F are also used for chamfering the edge of a
hole.
A cone formed at the extremity of a piece of pinion wire with a cutting
edge on each leaf and hardened will be found very useful for this
purpose.
=319.= The two forms of chamfering tool first described leave a series
of undulations on the bevel edge, so that, instead of being conical, it
presents a number of small facets. This inconvenience can be avoided by
using the tool shown at Z, Fig. 145.
A small disc of hardened steel is pivoted within a recess formed at
the end of a rod, the pin on which it rotates being at right angles to
the direction of the rod. As is seen in the figure to right of Z, the
section of this roller is a rectangle, and the surface is carefully
polished, the edges being left sharp.
Clockmakers make use of a tool for forming oil-cups that only differs
from the one above described in two particulars: (1) The disc is fixed
on its axis; and (2) the edge, instead of being square to the two
faces, is inclined as shown at _j_ and at the same time is slightly
rounded crosswise.
A few trials will be found necessary before the most convenient
thickness and inclination of edge are arrived at.
=320.= =Hollow Chamfering Tools.= These, as is well known, are used for
removing the angles at the ends of cylindrical rods, of steady-pins,
etc., or for rounding them off. Three forms are shown at O, Q, N, Fig.
146.
[Illustration: _Fig. 146._]
O is a round rod, the flat end of which has been filed across with
the corner of a triangular file. Four cutting edges are thus produced
which will act on the end of any object that rotates within them, or
_vice versa_. If it be required to form a very acute angle, two slits
must be cut with a screw-head file and the sides afterwards inclined
to the required extent with a flat file. This tool will serve a double
purpose: (1) to chamfer off the edge of a rod; and, (2) by prolonging
this operation to form a point at the end.
As a rule, when it is desired to round off, say, a pillar of a clock
after reducing its length or from any other cause, a hollow chamfering
tool of very open angle is used, a rocking motion being imparted to
it round the axis of the spindle; it is better to use a tool of the
shape shown at N or Q. The latter, Q, is easily formed by strokes of
a rat-tail file at right angles across its end; the other, N, is cut
internally with a shaped chisel or with a small rotating cutter to
which different inclinations are given during the cutting, as is also
done when using the chisel.
=321.= The tool shown at O, Fig. 146, has been modified as follows
by M. Roze. The two notches at right angles are replaced by three
equidistant notches of equal depth. To make these in a piece of round
steel it should be divided on the circumference into six equal parts;
then cut the three notches as follows: Calling the points marked on
the circumference 1, 2, 3, 4, 5, 6, one notch will lie parallel to the
line joining 1, 3, and equidistant between this line and the point 5; a
second will be parallel to 3, 5, and midway between that line and point
1, and the third will be parallel to 5, 1, and midway between this and
the point 3.
In a hollow chamfering tool thus constructed it will be found that only
the three long sides 1, 3, 5, actually cut, and at 2, 4 and 6 are short
sides that are set back. But when a file is laid on the face joining
two of the former sides, say 1, 3, the short faces 4, 6, will protect
the cutting edge 5 from contact with the file.
=322.= =Tool for Centering Rods.= These appliances are well known to
watchmakers, who often employ them for marking the position of the hole
in the brass wire when making bushings. It is advisable to have such a
tool somewhat large, about a third as large again as that shown at _s
r_, Fig. 147.
[Illustration: _Fig. 147._]
The head of the centering punch or drill is filed flat on either
side, and this flattened portion passes into a notch in the spring
_r_, which maintains it in position and prevents rotation when the
triangular-pointed blade is pressed against the end of this rod, this
rod being caused to rotate in the hollow cone of _s_. Instead of a
spring such as _r_, a helical spring is often used; but it then
becomes necessary to fix a pin in the drill that slides in a groove in
_s_, so as to prevent the drill from rotating.
=323.= =Centering with a Set-Square.= The set square may be used for
centering round rods, and the following is a very simple mode of
applying it:
[Illustration: _Fig. 148._]
On one arm of the square R, Fig. 148, a triangular plate _c d_ is
screwed or riveted so that its edge _c d_ exactly bisects the right
angle, that is, divides it into two equal angles. The flat end of a
round rod is held within the angle and against the plate, a line being
traced on it along _c d_; it is then turned through about a right angle
and a second line traced. The intersection of these two lines gives the
axis of the rod.
=324.= =Tool for Roughing Out Points.= This is merely the inverted
chamfering tool of which two forms are described in paragraphs
=320-21=, one of them being also shown at O, Fig. 146. It will be
evident that when the end of a rod is caused to rotate in this hollow
cone it will take its form.
In some cases it may be found convenient to place such a tool in the
tail stock of the lathe.
If the bottom of the cone at the end of O were prolonged by continuing
the cuts farther down with a thin flat file, the point of the rod might
be formed like a conical-headed screw before it is tapped.
=325.= =Balance-spring Collet Tool.= This convenient little tool for
rotating the balance-spring collet is commended almost as much by its
simplicity and facility of construction as by its usefulness.
[Illustration: _Fig. 149._]
A steel rod _n_, Fig. 149, is fixed in a handle T; it terminates in a
cone _a_ and is drilled with a fine hole as indicated by the dotted
lines. A thin wing _b_, pointed at its extremity, is also attached to
the handle.
Holding the balance between the fingers of the left hand and the
tool in the right, the blade _b_ is introduced into the slit in the
collet while _a_ rests on the balance staff shoulder, the pivot being
within the hole _n_. Now rotate to the right or left until the stud is
opposite to the mark on the balance rim, and this may be done without
danger, providing the tool is held firmly and vertical.
[Illustration: _Fig. 150._]
=326.= =Watch-hand Holder.= A very convenient form of tool, in which
to clamp a hand while enlarging the center hole is represented in
Fig. 150. Two brass plates, _f_ and _g_, are hinged at _m_ like a
sector. A collar, _a b_, surrounding the two is pivoted at _a_ and has
a clamping-screw _b_ by which the two plates can be forced together.
Several circular sinks of different sizes and equally divided between
the two plates, are cut of a depth varying from one-half to two-thirds
that of the plates, and they must be made to increase in diameter as
they get deeper, thus resembling the internal groove that receives a
barrel cover. The plate _a_ is cut away along the portion _c d_ and
grooves are formed to leave passages open between this surface and the
bottom of the sinks in _g_ and _f_.
When it is required to enlarge the hole of a watch-hand, place it,
inverted, in the hole of suitable size, as shown at _c_ of the figure,
and tighten the screw _b_. Held round the whole or greater part of
its circumference, the hand is thus firm and its center hole can be
enlarged without risk, either with a drill or broach; the hand will not
show marks due to the pressure with which it has been held.
=327.= =Common Hand fitting Pliers.= The sliding tongs with large flat
head, perforated with a number of holes in which the head of a hand is
clamped when the opening requires to be enlarged, are often useful,
but we feel them to be less so than the holder just described. It is
desirable that the inner faces of their jaws, which are usually left
rough, be at least smoothed.
[Illustration: _Fig. 151._]
=328.= =Another form of Watch-hand Holder.= M. Fiquemont has devised
the simple little tool shown in Fig. 151. It consists of a short brass
rod R, perforated lengthwise and having a thread cut externally on the
surface _a b_. It should be reduced in thickness below this tapped
portion. The rod, shown also in longitudinal section at P, is cut into
four quarters by two slits from _a_ to _b_, which are at right angles
and leave the points as indicated apart at _d_. The elasticity of these
four quarters should make them take the form of a reversed cone when
holding a hand, so that the ascent of the screw _c_ shall tighten them.
Within the head _a_ of the tool is formed a circular recess, so that,
if the reversed head of a watch-hand be placed within it and the screw
made to ascend, it will be held very firmly by the circumference, as
seen in the figure. The hand will thus be perfectly free to adjust in
any way that is needed for fitting it while held at the end of the
tool, and without being removed before the work is complete. Three or
four sizes will suffice for all ordinary watch-hands.
A tool may be made in a similar manner, except that the screw is not
divided by the longitudinal slits, and the hand is held against the
point by a lantern (similar to those of a screw-point tool), which
must be cut away in the manner indicated in Fig. 150, explained above
(=326=). An assortment of three or four lanterns will render the tool
serviceable for all sizes of hands.
[Illustration: _Fig. 152._]
=329.= =Clip for Holding Escapewheels while Cleaning.= A mere
inspection of M, Fig. 152, will make the arrangement of this little
tool evident. The fork is made of a piece of brass rod and its two arms
are elastic, a handle being screwed into the lower extremity.
Two small steel jaws are fixed to the upper ends inclined towards each
other, and, in using the tool, it is only necessary to press with two
fingers on the heads of the screws, when the jaws will open. Having
placed the escape wheel pinion between them, the wheel will be firmly
held so that its teeth can be easily cleaned, etc.
[Illustration: _Fig. 153._]
=330.= The appliance shown in Fig. 153 can be used for a similar
purpose, and is further especially serviceable for holding an
escape-wheel that is not riveted to its pinion. It consists of two
parts, a handle T, shown separate at _t_, which is drilled throughout
its length and tapped externally at the portion _t_, and a collar or
nut D, the end of which is traversed by two cuts at right angles that
resemble the letter =T= in section. If the tool is intended for holding
escape-wheels that have three instead of four arms, this cross must be
replaced by three radiating grooves of similar section. The position
occupied by the wheel is indicated by the dotted lines _r r_, and it
will be evident that, when the flat end of T is screwed up against this
wheel, after dropping it into the cross and slightly turning round
the axis as in a bayonet joint, it may be firmly held. The safest
mode of introducing the wheel is by holding it on a broach, which is
subsequently removed.
[Illustration: _Fig. 154._]
=331.= =Tool for Testing the Truth of a Cylinder Escapewheel.= The
small tool shown at D, Fig. 154, can be advantageously used in place
of the plain arbor commonly employed for testing the equality of the
spaces in such a wheel. The plate D, which may be mounted on three
feet, is traversed at its center by the smooth conical portion _f_
of the screw _f v_, tapped somewhat tightly into a cock fixed to the
other side of the plate. There is a radial slot, _a c_, cut in the
plate large enough to allow an escape-wheel pinion to move freely. An
inspection of the figure will make evident the manner in which the tool
is to be used: a wheel being placed as shown, or with reverse side
upwards, is made to slide towards the center, gradually raising the
screw until the largest space is found to admit _f_ with contact at
both sides. All the smaller spaces are then carefully opened until they
admit the cone in the same manner as the largest.
=332.= _Novel tool for the same purpose._ When the spaces are adjusted
in the manner explained above, or if the length of the teeth is
measured in a narrow gauge plate, there will nearly always remain a
certain degree of irregularity in the teeth. A more efficient means
would be for the gauge to embrace both a tooth and space, and this
condition is satisfied by the following appliance.
[Illustration: _Fig. 155._]
The slide _k k_, Fig. 155, is dovetailed into a plate, level with
its surface, so that _k k_ can be moved in a vertical direction by a
screw; it is perforated with a series of holes of gradually decreasing
diameter. To the same plate are also fixed: (1) a smooth tongue, _b_,
with a foot and screw; and (2) a second tongue, _j_, terminating in an
index _x n_, which is movable about a pivot, _x_, and held against a
pin in the plate by a light straight or spiral spring. The extremity,
_n_, traverses a graduated arc.
Having introduced the pinion of the wheel, or the arbor on which it is
held, into a hole of the slide that it fits without shake, and brought
this hole to the position indicated in the figure, apply a slight
pressure to the wheel in the direction of its rotation. With one tooth
resting against _b_ the tongue _j_ will be held by the spring against
the next and the reading of the index is to be noted accurately.
Withdraw the wheel slightly, and, placing the succeeding tooth against
_b_, take a second reading, and so on around the entire circumference.
Of course, the delicacy of the instrument will be increased by
lengthening _x n_ in comparison with _x j_.
[Illustration: _Fig. 156._]
=333.= =Tool for Removing Studs.= Fig. 156 represents a small tool
which may be employed for this purpose. It consists of a thick strip
of metal, C, spreading out like the letter T at the end which is not
shown, so as to form two feet, the screw, _j_, being a third, so
arranged that the T rests horizontally. The disc, _d_ (shown also
in plan), rotates on the screw, _j_, and is partially enclosed in a
horizontal slot. Around the circumference of _d_ are four rectangular
notches of different sizes. The holes indicated by black dots on the
plan receive the point of the screw, _v_, which clamps the disc when
the notch corresponding in size with the stud to be removed has been
brought under the small cone projecting from the spring, _b_; the other
end of _b_ is fixed to the T-shaped piece, C. The mode of using this
little instrument will at once be evident. Resting the right arm on the
bench, and, with the left-hand, bringing the wing of the cock above the
notch in _d_, the other hand presses upon the milled button of _b_,
forcing the conical pin against the stud and thus removing it from the
cock. The screw, _a_, can be adjusted so as to prevent too great force
being applied.
[Illustration: _Fig. 157._]
=334.= =Tweezers for Removing Studs.= One form is shown in Fig. 157.
The upper arm, H, is bent downwards as indicated at _g_. The lower arm
is shorter and carries a separate piece, _n m_, which slides under two
screws, _s_, and is pressed forward by a spring, _r_. The action will
be easily understood; the extremity, _m_, rests against the stud, and
_m n_ is forced backwards until the point, _g_, is exactly over the
stud pin. A simple pressure of the finger will then suffice to remove
the stud.
A still more simple pair of tweezers for this purpose may be made by
filling a square notch in the end of one prong of an ordinary pair with
broad noses, and setting a pin opposite to its center in the end of the
other prong.
=335.= =Staking Tool.= The modern staking tool will perform the same
work as the last two tools described and many other operations. It
consists of a shifting table, around which holes of various sizes are
arranged in a circle, so that any desired hole may be brought under
a suitable punch moving in a vertical holder. Usually twenty-four
tempered steel punches and four stumps are provided, which will be
found sufficient to cover all the operations in the ordinary run of
watch repairs, and the ingenious workman can from time to time add
to these by making punches in his spare moments, if he finds from
experience that he is in need of punches of a different shape. Fig. 158
illustrates the Johanson combination staking tool, on the front end of
which a hairspring stud indicator is arranged.
[Illustration: _Fig. 158._]
=336.= The staking tool can be used as a cannon pinion tightener by
making a punch for it having a blunt chisel edge. When a cannon pinion
is placed on a stump which is slightly dished in that portion of its
face opposite to the punch, and the punch gently struck with a hammer,
it will be sufficiently contracted to insure the requisite adherence to
the set-hands arbor. If fears are entertained lest the pinion should be
cracked with the blow, it may be placed loosely on an arbor and held in
position.
=337.= It may also be used to advantage for tightening the set-hands
arbor in the center or cannon pinion, but care must be exercised or
the arbor may be bent so that the minute hand which it carries passes
nearer the dial at one place than another.
An arbor that is too loose is introduced into a suitable stump and
at the top and bottom of the slack portion two punch marks are made
opposite one another. The punch having a conical or three-sided point,
will occasion an expansion of the metal round each mark; if a smooth
file be passed over the surface so as to remove the burr, which would
not offer any permanent resistance, sufficient projecting metal will
be left to secure a sound and lasting friction when a little oil is
applied.
If the arbor is well supported immediately beneath the punch, it
will not be distorted by any moderate impact. It is advisable before
operating on the metal to ascertain its degree of hardness.
=338.= It may also be used as a pinion riveting tool. The pinion,
with its wheel in position, is placed on the hardened steel stump,
the end to be riveted being upwards. The riveting is then struck
with the polished end of a hollow punch. If it be required to spread
the riveting, a punch must first be used that is rounded from within
outwards, to be followed with a perfectly flat punch. A little practice
will at once enable a workman to select the best form of punch.
The stump should be very hard and polished, funnel-shaped downwards
and carefully fitted to the bed, so as to be firm and central with the
punch. If these precautions are not taken the pinion will spring and
the riveting will be imperfect.
=339.= The staking tool may also be used for closing up barrel holes,
screw-holes, etc. In repairing watches it is often found that the
screws hold badly or not at all, and the holes at times cannot be
satisfactorily bushed. In such cases it becomes necessary to close
them, an operation which any intelligent workman can perform very
well in the following manner: Make a stump rounded at the top and
provided with a pump-center. This can be merely a pointed steel rod
that passes through the stump from below with slight friction, and
is forced upwards by a light spring fixed by a screw, so that, on
undoing the screw, the rod can be removed. The one pump-center can be
used for various stumps as the openings are funnel-shaped downwards.
Center the hole to be closed by means of the pump-center, then bring
down the hollow punch and strike it as in riveting a pinion. A small
circular groove will be formed around the hole, which, if the punch
is in good order, will be perfectly even. The form of the punch is
very important; the watchmaker must decide for himself by trial as to
the most convenient shape. The thickness of the ring of metal may be
modified; it is rounded off in a semicircle by some, and curved inwards
or outwards by others.
Instead of a pump-center below we have used punches that were
themselves provided with a pump center and helical spring. Either form
gives satisfactory results.
The holes of barrels can be closed with a punch that is only depressed
at its center enough to avoid the point of the pump-center. When the
face is more or less rounded the hole will be closed by forming a cup
as with a chamfering tool. The tool may then be enlarged if requisite
with a round broach or an arbor covered with white wax. It will thus be
hardened, and the cup-shaped recess will serve to retain the oil, while
the somewhat thinner hole will probably be in a condition to resist
friction as long as formerly.
When the hole is of moderate thickness, and it does not require much
reduction in diameter, this method will be found satisfactory; barrels
that have been thus treated have been found to stand ten years without
appreciable wear. When the metal is thicker, however, the spreading
inwards is very slight, and there is some danger, in using a round
broach to do it, of straining the metal or detaching the central ring
of the barrel or its cover.
It should be observed that the methods explained above are absolutely
useless for closing pivot-holes, and should only be resorted to for
barrels, on an emergency.
=340.= =Drifting Tool.= This appliance, shown in Fig. 159, is very
useful for making holes of round, oval or square, or, indeed, any
required form. It takes the place of a punching machine for light work.
[Illustration: _Fig. 159._]
The punch, or “drift,” is screwed into the stock C C′. A pin, _p_,
fixed in C C′ prevents its rotation while allowing an end motion
along the slot _m_ _n_. The end C′ is hollowed out to receive the
point of a screw, B, and a pin, shown near C′, is received in a groove
turned in B, thus enabling it to draw the stock in the direction C
C′. The part H is gripped in the jaws of a vise, and a strong handle,
E, is used to advance the screw B B′. With a tool about three times
the size of the figure there is no difficulty in punching the eyes of
mainsprings, square holes in stop fingers, etc., and it can be made by
an apprentice. Of course its strength depends on the pitch of the screw
and the radius of the handle E.
=341.= For heavier work it will be necessary to resort to the punching
machine. There are several constructions in use, but the most usual
is essentially the same as that of the tool just described. The screw
works vertically in a strong bridge that is fixed to the bed in which
the counterpart of the punch is held. Great use is made of this machine
in factories at the present day, almost every part of a watch being in
the first instance roughly shaped by its means. Indeed, thin metal is
often left as it comes from the punch, and very perfect crossings of
wheels, etc., are thus produced.
Steel does not cut well in the press unless it is soft and homogeneous,
and the final dimensions of the object can be more nearly approached
according as these conditions are satisfied. Attempts have been made
to cut levers, etc., of the exact dimensions required, but it is
better to leave a slight excess of metal to be afterwards removed by a
mill cutter or other means. The crossings of steel lever and cylinder
escape-wheels are punched out, but the metal used is of special
excellence. Before introducing a piece of steel into the press it is
advisable to remove any scale, etc., by pickling, or with a file.
=342.= =Draw-Plate.= Every watchmaker should possess a plate for
drawing round wire so as to be able to obtain it of any required
diameter. They are to be had at all material houses. In bushing holes
in a brass plate, it not unfrequently happens that the brass used for
the bushing is not of the same color as the plate. To avoid such a
difference cut off a piece from a plate of the same color and round
it by hand, making one end to taper. Fixing the draw-plate in the
vise, pass this end through one of its holes, and, gripping it in the
hand-vise, pull the brass through the plate. Continue this operation
through successive holes until the requisite thickness is attained.
No special precautions are necessary, further than keeping the holes
well greased and annealing the brass from time to time so as to
counteract the hardening caused by the operation.
Such a plate can also be used for steel wire, and plates with holes of
special form, for example those for drawing click and pinion wire, are
well known in the trade.
[Illustration: _Fig. 160._]
=343.= =The Grammaire, or Dividing Plate.= This tool is shown in
Fig. 160. To mark out the crossings of a wheel, etc., fix it by the
conical-headed screw _t_ to the middle of the plate, on which are
traced a series of concentric circles (not shown) divided into 6, 8, 10
and 12 equal parts. By laying the little ruler _r_ _r_ over the wheel
blank and using these division marks as a guide, 3, 4, 5 or 6 radii can
be drawn to serve as guides for cutting out the arms.
If it is desired to indicate the width of the arms instead of a mere
central line, a series of holes must be drilled at the division marks
and screws with tapered points tapped into them from below. Resting the
ruler against these cones, the arms can be drawn of any required width,
according to the distance to which the screws project. No further
explanation is necessary, for the figure shows: (1) a grammaire adapted
to mark out a four-armed wheel, these arms being indicated by the
dotted lines; and (2) the small ruler _r_ _r_ cut away at the middle so
as to avoid coming into contact with the conical-headed screw.
[Illustration: _Fig. 161._]
=344.= =Jewel-resetting Tools.= Hopkins’ patent jeweling and staking
tool, shown in Fig. 161, is an ingenious device, and one that will be
found very useful to the watch repairer. As the spindle, or handle, to
which the cutters and burnishers P P P are attached, is sustained in
upright position when in use, by the long bearings through which it
passes in the upright F, independently of the lower center, the hole
to be cut may be centered either from above or below as preferred; and
the depth to which it is desired the cutter shall work is regulated
by adjustment of the sliding collar E, and this being a correct
uprighting, as well as jeweling tool, with it a pivot hole, or a jewel
setting, the correct center (upright) of which has been lost, may
readily be corrected, or its true center again found, and, what in some
cases would be a very desirable consideration, by careful manipulation
with the cutter, which is under perfect control of the operator, the
position of jewel settings may be changed so as to alter the depth of
locking of the wheels to any desired extent. To regulate the depth to
which it is desired a cutter shall work below the surface of a plate,
lower the spindle D until, when moved out sufficiently far, the end
of the cutter will rest down on the top of the plate to be operated
upon, and fasten it there by lightly tightening the screw K; this done
adjust and fasten the collar E on the spindle D, to the same height
above the top of the upright F as it is desired the cutter shall work
below the surface of the plate on which it now rests. This, when the
spindle D has been again set free by loosening the screw K, will of
course allow the cutter to sink into the hole to be operated upon
to the exact distance the collar E had been set above top of F. In
adjusting the collar, E, the graduated wedge No. 4, or the jewel to
be set, as preferred, may be used as a gauge. The burnishers, No. 9,
are used both for opening and closing settings; the same burnisher,
having chosen one of proper size, is used for both purposes; the side
being used for opening the setting, and the beveled and rounded end
for burnishing it down again over the jewel. The pieces 13 and 14 are
made to fit in the lower end of the spindle D (the cutter P having been
removed), same as an ordinary drill-stock, and are used for burnishing
the edges of a jewel setting down flat over the jewel, countersinking
screw heads, giving end-shake to wheels, etc.; and being easily made,
any one owning the tool can make these for himself, of forms and sizes
to suit the particular work in hand. For uprighting purposes, withdraw
the spindle D and substitute No. 5, the rings, No. 3, being intended
for laying the work on, on the tool bed. For upright drilling through
watch plates, mark the place to be drilled (prick punch it slightly)
with the cone point of No. 5; which done turn the spindle No. 5 upside
down and rest the upper end of the drill in the countersink in its end,
the drill being operated with a fiddle bow acting on a collet placed
on its shank for the purpose. For cutting off bushings level with a
watch plate, either a cutter of the No. 13 or 14 class, or one of the
P cutters can be used. For staking or riveting wheels upright on their
pinions, lay the stake No. 7 level on the tool bed (the center M having
been fastened down out of the way), and with No. 5 center accurately
the hole to be used in the stake, and fasten it there by means of the
clamps N; then remove the cone end of No. 5, and place a punch with a
hole in its end of the required size, on the part _m_, and proceed as
in an ordinary upright staking tool.
=345.= =Tool for Flat Polishing.= A thick brass plate is provided with
three strong screws arranged in triangular form (G, Fig. 162), and
far enough apart to ensure that, if the plate is reversed and rests on
their heads, it will remain flat when moved by hand over a polishing
surface.
[Illustration: _Fig. 162._]
The screws should fit tightly or be provided with lock-nuts.
We believe that every watchmaker must be acquainted with this little
tool. The object to be smoothed or polished is fixed with shellac or
sealing-wax to the middle of the triangle formed by the screws; the
level is then adjusted so that, when resting on a flat surface, the
object to be polished coincides exactly with it. The polisher (for
example, a sheet of ground glass) is charged with oilstone dust or
polishing rouge, and the object is passed over it until perfectly flat
and smooth.
=346.= For smoothing, it is best to use a large sheet of iron or steel.
For polishing, copper or bronze is preferred. Ground glass may be
employed for both operations; it must be hard and perfectly flat.
A disc rotating in the lathe or mandril, etc., is often used.
The tool may be inverted and rest firmly on a cork, the polisher being
then moved backwards and forwards by hand, and always in contact with
the three screws.
It is best to use pith for cleaning the polished surface; in its
absence use soap, then wash and dry with a soft linen rag. The object
is detached by heating the tool, and is cleaned by boiling in alcohol;
afterwards pass through pure alcohol at the ordinary temperature and
dry.
=347.= This tool can be employed for polishing small surfaces, such as
the end of a rod, of a barrel-arbor or a screw-head, as well as for
those of greater extent. But it appears needless to enter into further
detail.
Instead of three screws some workmen only use two, at some distance
apart. The object to be polished, being placed at the third corner of
the triangle, takes the place of the remaining screw.
Lastly, if a band be fitted to one side of the brass plate, as shown at
_b_, Fig. 162, and held by two screws, it will often be of service as a
clamp for fixing the object, as at _s_.
=348.= Flat pieces can be polished on a revolving lap worked by the
foot, being simply held in the hand or in a piece of soft leather; but
a certain amount of practice is needed in order to do this successfully.
ACCESSORIES
AND MISCELLANEOUS OPERATIONS TO BE PERFORMED IN THE UNIVERSAL HEAD.
=349.= With a view to simplify the work, we will here give, in a
collected form, a number of operations that may be performed in the
mandril, or universal head, among which the practical watchmaker will
easily be able to distinguish those that can be done in the ordinary
lathe; we will also describe numerous accessories that the workman
should make for himself, if he is desirous of making his mandril or
universal head still more generally useful.
[Illustration: _Fig. 163._]
=350.= Prepare a number of chucks of the form shown in Fig. 163. Some
of these carry a small bar with screws, by which an object may be
clamped firmly to the chuck, an arrangement which is also shown at A,
Fig. 163; others have a hole drilled through their axis; others again
have a projecting arbor, etc. They may also be made with a flat face
on which to cement objects in the ordinary manner.
[Illustration: _Fig. 164._]
As it is often necessary to have a considerable surface to cement, for
example, a watch-plate, one or more may be made of the form shown at T,
Fig. 164. The lower plate being clamped in the dogs, the disc _e_ will
be free. If this disc be made of bronze or steel it may be used as a
lap; if of brass, it may be turned true and used as a wax chuck, etc.
The chucks should, as far as possible, be well made, so that they can
be truly centered by means of the pump-center.
TO CENTER AN OBJECT.
=351.= When there is a hole at the center on the side towards the
face-plate, in the universal head, as is usually the case, it is only
necessary to place this hole over the point of the pump, pressing it
inwards, and then to clamp the object in the dogs; the pump is then
drawn within the body of the arbor. Very often, however, there is no
central hole, or there is only a mark on the face that is towards the
cutter; in such a case it becomes necessary to center from the front or
by the circumference.
=352.= =To Center from the Front.= If the object is held by wax on a
plate, it may be centered as in the ordinary lathe while the plate is
hot, by resting a piece of pegwood on the T-rest with a point placed in
the central hole, and observing whether its free end remains stationary.
After the plate has cooled, the accuracy of the centering should be
tested by means of a long piece of pegwood which rests on the T-rest
brought close up to the object. The pegwood is held parallel to the
lathe-bed, and, if the centering is satisfactory, its outer end will
not move. The detection of any slight movement is greatly facilitated
by placing some fixed object close to the free end of the pegwood. If
a motion is still observed the centering is imperfect, and must be
corrected in the manner explained below (=354=).
=353.= _Perrelet’s method of Centering._ In principle, this is
identical with the one just described; but the pegwood index is
replaced by the small apparatus shown in Fig. 165.
[Illustration: _Fig. 165._]
A hollow cylinder, of which _a c c a′_ is a section, is firmly held by
friction by its portion a _b b′ a′_ in the tailstock. In the front of
this cylinder is fixed a steel ring that is thick at the circumference
and tapers inward, so that the central hole has a cutting edge. The
two black triangles represent a section of this ring. The rod _r_ _n_
passes without play through this hole, and carries a projecting ring
at _s_ to determine the distance to which it enters the collar _c c_;
there is also a small key that corresponds with a nick in _c c_, and
thus prevents rotation.
An inspection of the figure will show that, when _s_ rests against _c
c_, if the finger be placed on _r_ and communicate motion to it, the
rod _n r_ will be able to oscillate in any direction, and to an extent
limited by the diameter of the hole in the cylinder.
The error in the centering at _r_ will be multiplied at _n_ in the
proportion of _n s_ to _s r_; thus if _n s_ is ten times _s r_, the
motion at _n_ will be ten times as great as the actual error at _r_.
=354.= The instrument is used as follows: The object to be centered
being placed between the jaws, having the centering spindle in
position in tailstock. Slide tailstock towards the face-plate until the
point _r_ of the rod enters the hole, or central mark of the object,
and, setting the T-rest close to the point _n_, rotate the face-plate.
If the centering is exact, the point _n_ will remain stationary. If _n_
moves to and fro, give a gentle blow against the edge of the object,
which should not be held firmly in the dogs; the blow must be on the
side opposite to that at which _n_ shows the greatest deviation from
the point of reference. Repeat the process until the centering is
perfect or sufficiently accurate; then clamp the dogs firmly, taking
care not to disturb anything.
In centering from a jewel hole, an aluminium rod _n s_ may be employed
on account of its lightness, and it may be terminated in an ivory cone
at _r_.
=355.= There is one precaution to be observed, as it facilitates the
use of this appliance; it is advisable that the portion _a b b′ a′_
of the cylinder be somewhat long and well made, in order that, while
being in the first instance inserted in tailstock up to the shoulder,
the cylinder may be partially withdrawn and still held firmly. The
reason for this is as follows: When the tailstock is pushed along, a
considerable amount of friction resists its motion, and, as the hand
cannot always control this motion, it may happen that _r_ comes up
against the object with some force. To avoid this, bring the point near
the hole and then rotate the collar in the tailstock so as to gently
withdraw it to the requisite amount. The cylinder may, if desired, be
fixed by a small screw after the point _r_ has been set in position.
[Illustration: _Fig. 166._]
=356.= =Another Centering Device.= The centering indicator shown in
Fig. 166 will also be found useful for testing for exact center. The
body of the indicator is made of sheet brass, and should be about five
inches long by two inches in width at the larger end. The shank _C_
is made to fit in rest holder, and is either riveted or soldered to
the body; _R_ is steel or copper wire sharpened to a fine point, and
balances on a pivot at 1; _B_ is a clock hand pivoted to the body at
1; 2 and 2 are pivot joints only, and do not go through the body; _C_
will perhaps give a better idea of the end _R_. To center with this
tool, unscrew your rest and remove it, then place the shaft _C_ in rest
holder and adjust it till the needle point _R_ touches the top of hole,
as shown at _A_. The index hand will then note the variations as the
head revolves. If too low, the hand will point above center, and if
high, vice versa.
=357.= =To Center from the Circumference.= Two cases may occur:
Either the entire rim of the object is exposed, as when the teeth are
to be cut in a wheel blank; or the rim can only be used as a means
of determining the center, as when a barrel has been bushed with an
undrilled bushing.
=358.= The tool shown in Fig. 166 may also be used for the test if the
short end of arm R rests against the under side of the object that it
is desired to center.
=359.= When it is required to drill or merely to center the hole in a
wheel, barrel, etc., that does not run true, clamp a piece of sheet
brass in the dogs and turn out a sink that will exactly receive the
wheel, etc., but allowing it to project slightly. Now unscrew one dog
and advance it a little, so as to grip the edge of the object as well
as the plate; move the other dogs inwards in succession, and it will
only remain to drill or true the hole with a suitable drill.
UPRIGHTING AND DRILLING.
=360.= =When the Lathe is Provided with a Tailstock.= Let it be
required to mark and drill a pivot-hole in the cock when the plate-hole
is accurately centered by means of the pump-center. Place the tailstock
in position on the lathe-bed, and mark the position of the hole with a
center, as in an ordinary uprighting tool; then, if the hole is to be
very fine, make it with an ordinary pivot-drill.
If the hole to be drilled is somewhat large, it may be drilled with the
twist drill, the bed of the lathe being, as usual, horizontal.
=361.= =When the Lathe is not Provided with a Tailstock.= In such a
case it is possible to upright and drill by using fine drills, and
making points so formed as to take the place of the cutter. Or a stock
may be made to receive drills, points, etc., and it may be well here
to remark that stocks of the same form are convenient for receiving
chamfering or sinking tools.
[Illustration: _Fig. 167._]
This stock is shown in Fig. 167. An inspection of E _c_ will suffice
to show its form, and it may be used for holding either a drill or a
marking point, or a small hollow center in which to support a pivot
drill.
The following method should be adopted for securing accuracy in the
adjustment of these stocks:
There must be no shake of the stock in the tool-holder; it is
especially important to avoid any displacement during the act of
clamping. If there is any reason for doubt on this point, drill a hole
at the foot of the cutter in which an index, _y_, can be temporarily
inserted; any displacement can be detected by its deviation from a
fixed mark. As a rule, however, there will be no occasion for doubt if
the plate that is screwed down upon the stock is parallel to the bed of
the tool-holder.
The cutter is then replaced by a stock of the form shown at E′, in
which a hole has been previously drilled to receive the drill or other
bit, but somewhat smaller than it is required finally to be. The
pump-center must now be replaced by an accurately fitting piece B that
terminates in a short semi-cylindrical drill.
It will be evident that if the mandrel be revolved, and, at the same
time, the tool-holder advanced towards this drill, the hole in the
stock E′ will be enlarged and smoothed, and its axis will accurately
coincide with that of B. Any drill, chamfering tool, etc., that has
been turned true, will, therefore, on being inserted in the stock,
prove to be strictly in the axis of the lathe.
[Illustration: _Fig. 168._]
=362.= =To Drill a Series of Holes.= Mount on a stock similar to that
just described, a small frame carrying a drill-stock, as shown in Fig.
168. If this be fixed in the slide-rest in place of the cutter, it can
be used for drilling a hole or a series of holes previously marked out,
or, if the pitch of the transverse screw of the slide-rest is known,
for a series of equidistant holes in a horizontal line. When it is
required to drill a series of holes in a circle, as, for example, in
the escape-wheel of the pin-escapement, bring the point of the drill
onto the circumference and then proceed as when using the ordinary
wheel-cutting engine provided with a vertical drill-holder, taking care
to fix the face-plate by means of an index.
This index should have a means of slightly modifying its length,
so that the point of the drill may always be brought into exact
coincidence with the points that have been previously marked on the
object.
It will be observed that, if the drill were replaced by a round milling
tool, the U’s of a cylinder escape-wheel might be polished, or, indeed,
cut, the concave ends of the teeth of the star-wheel in a Geneva
stopwork could be corrected, etc. But it is unnecessary further to
insist upon the many uses to which this form of tool can be applied.
=363.= =To Cut the Teeth of a Ratchet, Minute-Wheel, Etc.= When the
face-plate is divided on the circumference, it is easy to cut the teeth
of an ordinary wheel of a timepiece, escape-wheel, barrel ratchet, to
cut or true a star-wheel for the stopwork, etc. After mounting the
wheel on a chuck and carefully centering it, replace the cutter by a
small revolving cutter-frame after the model of that shown in Fig. 168.
The stock _d_, shown in both plan and elevation, carries a piece _c_
at right angles, which has a slot cut throughout its length. In this
slot a U-shaped support can be clamped by a nut in any position. The U
portion forms a bearing for a cutter, such as is shown at _f_ in the
figure, and the axis projects so as to receive a ferrule for rotating
the cutter.
It will be evident that, with such an arrangement, the height of the
cutter can be adjusted in accordance with the teeth to be cut.
=364.= =To Cut a Circular or Elliptic Groove.= For this purpose no
special accessory is needed; an ordinary cutter will suffice.
[Illustration: _Fig. 169._]
Let _a b c d_, Fig. 169, be the form of the required groove. Mark a
series of centers so that circles struck from them will just overlap
one another, and at the same time nearly reach the edge of the groove.
Then turn out all the circular sinks, indicated by shaded lines, to the
required depth.
Center the plate by the point _o_ from which the arc _a b_ is struck;
now bring the cutter to such a position that its outer cutting edge
coincides with the arc _a b_, and bring it against the plate; set the
face-plate in motion, not, however, by using the treadle, but by the
hand at its circumference, and traverse the arc from _b_ to _a_; then
withdraw the cutter. By this means the projecting angles, left white
in the figure, will be removed, and a clean edge will be left to the
groove.
As an operation of this description will not present any difficulty,
further explanation appears unnecessary; for the information above
given will enable any watchmaker to make curved grooves of the kind
indicated.
If it is required to smooth the surface of the groove, replace the
cutter by a pegwood stick that can be rotated with friction, and
the end of which just fits into the groove, charging it with pumice
or other stone and oil. One hand moves the face-plate backwards and
forwards, while the other rotates the stick.
[Illustration: _Fig. 170._]
=365.= _To Cut the Cylinder Escape-Wheel Cock Passage._ As a rule the
cock is cemented, inverted, to a wax chuck, and the passage cut or
enlarged on the lathe. It is more expeditious to use a plate provided
with a clamping bridge, as shown at Fig. 170. The face-plate should be
made to oscillate backwards and forwards by hand, and not rotated by
the wheel.
=366.= =To Make a Straight Groove.= _First method._ The tool devised by
M. Chopard, director of the school of horology at Besançon, and shown
in Fig. 171, is used for this purpose. As will be seen, it consists of
a small lathe which is adapted to the slide-rest as follows:
[Illustration: _Fig. 171._]
Two pins, _a a′_, are planted in the top of the tool-holder, the
cutter together with the plate by which it is clamped having been first
removed. Holes drilled in the frame _f f_ fit accurately onto these
pins, while a screw, _h_, passing through an intermediate hole, affords
a means of firmly fixing the apparatus to the tool-holder M.
This tool should satisfy the following conditions: The arbor C should
fit into a recess that receives a cutter, but without coming into
contact with it; this arbor should be parallel to the bed of the lathe;
and, lastly, the axis of C should be on a line with the lathe center.
=367.= Having set this little appliance in position, trace on the
watch-plate two lines indicating the directions of the sides of the
groove as well as lines fixing its length. Now place the plate in the
dogs, setting the point of the pump-center anywhere on the line drawn
along the middle of the groove. Turn the plate so that this line is
horizontal, and fix it in any way that is convenient.
The arbor C carries a revolving cutter _k_, which can be changed as
desired, and is held in position by the clamping screw _d_. Assume
that the diameter of this cutter corresponds exactly with that of
the required groove; advance it towards the plate, turning the wheel
rapidly, the cord being round the ferrule _b_; a circular sink will
thus be formed in the plate of the same diameter as _k_.
When this has been cut to a sufficient depth, the tool is moved
parallel to the face-plate, and the cutter _k_, continuing its movement
of rotation, will now cut, not with its extremity _i_, but with its
sides. It will thus form a straight groove of any desired length.
=368.= The cutter is a three-sided prism, or it may have four sides
with four cutting edges on the sides, and only one cutting edge at the
extremity _i_. If it is preferred to retain only the two acting edges
that start from either end of the cutting edge _i_, they may be made
more acute, and the other pair reduced by means of a file.
[Illustration: _Fig. 172._]
=369.= _Second method._ This is simpler than the one just considered.
At the end of a rod G, Fig. 172, which takes the place of the cutter
in the slide-rest, a plate _p_ is fixed. A line is drawn across the
face of this plate in such a position that, when G is clamped in the
tool-holder, this line is horizontal, and in the plane that contains
the axis of the pump-center.
Let it be required to cut a straight groove in the piece of brass _l_.
Wax it to the plate _p_ so that the axis of the required groove is over
the line traced on the plate. Now fix G in the tool-holder and replace
the pump-center by a rod D, the extremity of which is formed into a
cutter of a diameter equal to the width of the required groove; the
rod D should be fixed in the hollow arbor by a screw. It is then only
necessary to set the cutter in motion, forcing the piece _l_ against
the revolving cutter, until the requisite depth is attained. Then, by
making the tool-holder travel parallel to the face-plate, the groove
will be elongated until of the desired length.
=370.= The cutter may be of the form shown in Fig. 171, or it may be
as shown at _b_ in Fig. 172, since the movement is always in the same
direction. The cutting edges are each formed by two small inclined
faces, one pair of which is shown at _b_; they occupy half the diameter
of the cutter. At the back of this pair the cutter presents the
appearance of the lower half shown in the figure and _vice versa_.
It will be evident that the two sides of this cutter will act while its
motion is continuous in one direction.
Besides the numerous operations that can be performed on the lathe as
we have hitherto indicated, it may be employed, if divided on the head
stock, for tracing out angles, marking the crossings of a wheel, a
balance, etc., and for other purposes, many of which are referred to in
the course of this work.
PRODUCTION OF SCREW THREADS.
SCREW PLATES AND TAPS.
=371.= The lathes employed in the manufacture of screws are of two
kinds; those intended for polishing and, where necessary, modifying the
form of screw-heads, much used by watch examiners and repairers, and
those specially designed for cutting the threads, which are mainly in
use in factories.
Before discussing them, however, we will give some account of the
screw-plates and taps in ordinary use.
=372.= =Common Hand Screw-plates.= The use of these is much facilitated
by providing a second plate perforated with holes of such sizes that
a spindle which just passes into a hole of any given number will be
of the size most convenient for forming a screw in the hole of the
same number in the screw-plate. For a long time we have made use of
two Latard screw-plates so made that a rod which would enter one hole
without play was of the most convenient size for forming a screw in the
next smaller hole but one (thus the plate perforated with plain holes
can be replaced by a second screw-plate, or by using the successively
larger holes on a single plate as gauges).
[Illustration: _Fig. 173._]
In order to form a screw that is clean-cut and even, with the least
possible straining of the metal, the holes in the screw-plate should
have notches cut as shown at F, Fig. 173; they should be carefully
hardened and well polished on each side of the notch, and this system
is now even applied in the case of the smallest jewel screws.
=373.= =Screw Dies.= The ordinary plate, in which notches are not cut
at the sides, squeezes up and strains the metal. This effect is less
marked when separate dies are used, and disappears entirely if only
a small quantity of metal is removed at a time, and the cutting edges
of the dies are smooth and in good order. In addition to possessing
other advantages, this form of screw-plate enables us to obtain at
will screws of the same thread and different diameters or of the same
diameter and different threads. The dies must be carefully fitted to
the slides that receive them. Dies cannot be employed for cutting very
small screws.
=374.= =Fine-threaded Screw-plates.= At the present day these can
always be obtained at the material stores; but thirty years ago it was
not so, and the watchmaker was obliged to make them for himself. The
following method was adopted:
Take a screw formed with an ordinary plate, in which the thread is
broad as compared with the hollow. If the screw does not satisfy this
condition it must be modified thus:
Having ascertained that it runs true, and that it is larger than will
be ultimately required, insert it in a chuck in your lathe. The T-rest
must carry a smooth horizontal rod of hardened steel.
Rotating the screw, hold a slitting file in the hollow; the file
should fit into this hollow accurately, and should be smoothed on its
two sides, only cutting with one edge. The bar of hardened steel will
determine the depth to which the file is allowed to cut. By this means
a screw is obtained that has a thread thick at the bottom. With the
graver remove the top of this thread, round off its corners, and harden
the screw, filing three facets along its entire length, that make it
taper.
The tap, having been thus prepared, is employed for cutting a thread in
a piece of steel, not too thick, that has been previously annealed,
and in which a hole is drilled of the proper size. The thread of this
internal screw will be thin and the hollow proportionately broad.
The plate is now hammered cold with care until the thickness is so
far diminished that the thread and hollow are as nearly as possible
of equal thickness. Harden it and chamfer the ends of the hole with a
conical steel point and oilstone dust. Then clean it and cut a thread
on a piece of soft steel which may be formed into a tap.
If the operation has been properly conducted, this tap will satisfy
the prescribed conditions, and, when hardened, it is to be employed
to cut a thread in a second steel plate, which will be employed as
a screw-plate; for that first formed must, in consequence of the
hammering to which it was subjected, present irregularities in the
hole, and can only be used to cut one or two taps cautiously. It is
useless for making screws or tapping brass. (See also =378.=)
=375.= _To Clear a Stopped Hole in a Screw-Plate._ Drill a hole through
the center of the piece of metal that fills up the hole, taking care to
maintain it central, and to employ a drill that is sufficiently small
to avoid all risk of contact with the screw threads. Pass a broach
through this hole and, after tightening it with a few gentle blows
with the hammer, turn it in such a direction that it tends to unscrew
the broken screw, which will in nearly every case, be removed without
difficulty by this means.
TAPS.
=376.= Screw-cutting comprises two distinct operations—the formation of
a spiral thread on the circumference of a cylindrical spindle, and of a
spiral groove within a cylindrical hole to receive this thread.
Taps are made either by means of a screw-plate or in the lathe; we
shall presently refer to this second method. Every watchmaker may be
supposed to have received, early in his career, instruction as to the
cutting of a tap with a screw-plate. Great caution is necessary in the
hardening, for if the tap is not true or the metal burnt it will cut
badly and be apt to break. Taps are cleaned after hardening with a
piece of wood in the lathe or between two hard pieces of pith covered
with oilstone dust, and either three or four cutting facets may be
made. It is important to avoid the production of a burr in making these
facets; a good plan is to make them while the metal is still soft, and
to pass the tap through the plate subsequently, as a sharp cutting edge
is thereby produced. The facets should be carefully smoothed, and the
use of coarse rouge is an advantage.
A tap with three facets gives the cleanest cut and leaves the most
space to receive the metal that is removed, but with four facets the
roundness of the hole is more certain to be maintained.
[Illustration: _Fig. 174._]
We have seen taps formed as represented at M, Fig. 174, so that the
object in which a thread is being cut is loose at the part _o_, when
the direction of movement of the tap is reversed. They are also at
times made semi-cylindrical, as at G, and work well in the lathe for
tapping brass, but we have not tried this form with steel.
=377.= =To Cut a Tap when of Considerable Length.= The following
precautions must be observed in order to ensure that a long screw shall
be both round and true.
The steel must be of very goad quality, and loose dies should be used
in preference to a screw-plate. It is a good practice to employ two
pairs of dies (or even more); one to rough out the screw, leaving the
thread somewhat larger than it will finally be, and the other to finish
after having trued it, and even sometimes lightly turned the surface in
places. Very little metal must be removed at a time, the dies should
have sharp cutting edges, and a rather large number of threads.
A screw can be made in the ordinary manner in a screw-plate rather
larger than is required, then reduced to the requisite diameter, and
finished with a plate in which the holes are of the form shown at F,
Fig. 173, or in a screw-cutting lathe; in either case, however, care
must be taken to avoid straining the metal in its passage through the
first plate, on account of the tendency which it then possesses to
become distorted in the hardening.
If a micrometer screw is required, that is, a screw of absolutely
uniform pitch, it is necessary to apply to makers of astronomical and
other similar instruments of precision.
[Illustration: _Fig. 175._]
=378.= =To Cut a Screw of any Desired Pitch and Diameter.= Let it be
required to cut a thread on the stem B, Fig. 175, of any pre-determined
pitch that already exists in a screw-plate. Turn down the portion _d_
to such a diameter that a screw can be cut on it in this hole, and fit
two runners to the lathe of the form shown at G and H. The end of H
is drilled and tapped so that _d_ turns freely in it, and a hole is
drilled in G to receive the stem B freely, but without sensible play,
and a fine notch is cut at _a_.
It will be obvious that if now the ferrule _r_ is caused to rotate,
while a fine saw or file is inserted in the notch _a_, a screw will be
formed on B of the same pitch as that on _d_, although there may at the
same time be a very considerable difference in their diameters. This
method may be adopted in place of that explained in article =374= for
obtaining a fine-threaded screw.
=379.= =Left-handed Screw Taps.= The manner in which these are made in
the screw-cutting lathe will be subsequently explained; in its absence
the watchmaker may adopt one of the following methods:
[Illustration: _Fig. 176._]
_First method._ If, when an internal screw has been cut with a
right-handed tap, B, Fig. 176, it be required to tap a second hole in
the reverse direction, the following plan may be resorted to:
File the original tap B on two opposite sides, so as to give it the
flattened shape shown at A in the same figure. Insert the end into the
hole to be tapped and turn the tap to the left with the application of
considerable pressure, so as to force the tap to bite. When the tap has
been passed in and withdrawn there will be found to be a left-handed
thread cut in the hole. For, if the tap is turned towards the right,
the thread _f_ passes into the groove already formed by the thread _a_;
but, if turned towards the left, _f_ will originate a groove into which
_b_ will pass, traveling in an inverse direction to that previously
given to it.
The finer the thread of the screw, the better is the chance of success,
and with a wide thread it is often necessary to recommence two or three
times. If a plate or pair of dies be cut in this manner and hardened,
they will serve to cut an even left-handed tap.
[Illustration: _Fig. 177._]
_Second method._ Attach a comb to one or two sides of a cylinder, as
indicated at F, Fig. 177. This can be used to cut a thread in the
piece of metal S, that is either right or left-handed according to the
direction of rotation of F, sufficient pressure being at the same time
applied to force it into the plate. The pitch of the thread will depend
on the amount of pressure applied. This plan is only a modification
of the one described above, and, as in that case, success can only be
guaranteed when a means is adopted for securing a definite relative
amount of motion in F around its axis and S vertically.
[Illustration: _Fig. 178._]
_Third method._ A tap of unhardened steel is filed into a triangular
form, C, Fig. 178, and twisted so as to bring the angles _b_, _f_,
towards _a_, _d_, etc.; we thus obtain a tap which will serve,
throughout a certain portion of its length, to cut a left-handed
thread, but the part that is not so adapted, at the extremities, will
require to be removed before hardening.
[Illustration: _Fig. 179._]
=380.= _To Make a Left-handed Tap by Means of a Right-handed Tap._ A
portion of the right-handed tap is filed off on three faces to the
section shown at _b_, Fig. 179, and firmly set in the die _d_ so as to
be held in the frame for screw-cutting dies. A second die, _f_ made of
brass and having a semi-cylindrical recess opposite _b_ is fitted to
the frame. The diameter of this semi-cylinder should be the same as
that of the rod on which a left-handed thread is to be cut. Now grip
this rod as shown at _a_ by means of the screw _g_, so that it is held
between the die _f_ and the block _b_, and rotate the frame or the rod
_a_ towards the left; a spiral groove will thus be cut by the thread on
_b_. It is sometimes an advantage to cut this thread lengthwise in the
manner indicated at _b′_.
[Illustration: _Fig. 180._]
This method enables us to cut a given thread on a rod of any given
diameter. From an examination of Figs. 179 and 180, it will be seen
that a simple comb of the form of C or D, carefully made by hand
and fixed in the place of _b_, can be employed to cut a right or
left-handed thread on any given rod; it is advisable, however, that the
teeth of the comb be inclined to the axis of the screw, like the thread
of an ordinary tap, as otherwise the operation becomes more difficult
and success less certain.
[Illustration: _Fig. 181._]
The method may be simplified by taking a brass plate, D, Fig. 181, of
sufficient thickness, and firmly setting in it the right-handed tap,
_v_, having only filed away two opposite faces before hardening. The
rod to be tapped is then introduced with considerable pressure into
the hole _j_, and, if rotated towards the left, it will receive a
left-handed thread of the same pitch. The notch shown at _b′_, Fig.
179, will facilitate the operation, as a cutting action will take the
place of compression.
=381.= M. Gontard has suggested a modification of this arrangement,
which consists in forming the die _f_, Fig. 179, so that the original
right-handed tap can be embedded in a hole previously tapped in it and
filed away on the side towards _b_ so as to expose a cutting edge; and
he points out that, by suitably inclining the frame with reference to
the axis of the rod to be tapped, the appliance can be used to cut
a double or even a triple-threaded screw, right or left-handed. He
further draws attention to the fact that in a screw formed in this
manner the sides of the thread are smooth and polished, a condition
which cannot be secured when either a plate or dies are used.
=382.= =To Increase the Diameter of a Tap.= It sometimes happens that
a screw will not penetrate to a sufficient depth, or fits too tightly
into its hole, owing to the tap employed being of a less diameter,
either in consequence of the hardening, polishing or wear, or through
having been formed in a different screw-plate. In such a case the
following expedient may be resorted to:
[Illustration: _Fig. 182._]
Make a fresh tap in soft steel and file away two opposite sides so
as to give it the section shown at A or B, Fig. 182: after measuring
the diameter at several points in its length, hammer gently on the
flattened sides. With a little care and by using a micrometer at
intervals for testing the alteration in diameter, it will be found that
the required increase can be obtained without much difficulty. The tap
is then hardened and polished, etc.; indeed, it is best to make a fresh
tap.
METHODS OF TAPPING HOLES.
=383.= It is needless to refer to the method of tapping by hand, as it
is well known to all practical men.
=384.= =Tapping in the Lathe.= The plate of a watch is gripped in the
dogs of a face-plate, the hole to be tapped being centered by means of
the pump-center, which is then withdrawn, and a tap held to the hole;
the face-plate is then caused to rotate either by the hand resting
on its circumference, a slight backward motion being given after each
advance, or the motion may be continuous and be given by the wheel. In
the latter case, however, the tap must have a good cutting edge and
only be held in the hand with the degree of force required to make it
cut, so that it may rotate without breaking in case the resistance
opposed becomes too great. The tap may be steadied on the T-rest.
=385.= =To Tap with a Mainspring Winder.= The ordinary mainspring
winder will, if the click work is removed, be found very convenient
for tapping holes, and indeed, for forming the external thread on
screws. Having removed the winding arbor, replace it by a tap carefully
centered; then introduce its coned end into the hole in the plate,
which must be pressed forward while the handle is turned, a short
backward motion being given to it at frequent intervals. When the tap
is engaged sufficiently in the hole it is merely necessary to maintain
the plate at right angles without applying pressure.
=386.= =To Tap with a Bow.= Instead of the mainspring winder, one of
the small drill-stocks to be driven by a bow, consisting of an arbor,
with a coned hole at one end and ferrule at the other, supported in a
frame that is clamped in the vise, may be used. They are to be obtained
at any tool-shop.
The bow being on the ferrule and the tap properly centered in the
arbor, the hole is held against the coned end and the bow worked with
an alternate forward and backward movement; but if the tap has a good
cutting edge and the bow is strong (of steel or cane), a hole may be
tapped with a single stroke of the bow. After a few trials the method
will be found very easy and certain.
A regular and rather slow motion should be given to the bow, which
should be long and strong. It is well to ascertain the number of
revolutions of the ferrule that correspond to a stroke of the bow, so
as to ensure that the tap is not introduced to a greater depth than is
required. If it is desired that the screw work easily in the hole, the
tap should be moved several times backwards and forwards.
=387.= The little turns here referred to, some of which are perforated
throughout their entire length and others only at one end, are very
cheap and will often be found useful; they can be adapted to receive
drills, broaches, taps, etc.
=388.= =To Tap in an Ordinary Lathe.= In factories it is a common
practice to tap the holes in plates, etc., and even to cut the threads
of screws in a lathe specially arranged for the purpose. The tools
adapted for such work are of two kinds: in some the tap enters to the
required depth, when it is immediately arrested, disconnected, and then
rotated in an opposite direction; in others, the tap advances to a
definite point, and is immediately withdrawn. As a rule, however, the
tap remains stationary and the object is caused to rotate.
=389.= =Beillard Lathe for Tapping Screws.= The axis F M, Fig. 183, is
perforated throughout its length. At F, the screw-plate G is dovetailed
into it. The inner end of the hole in this plate is slightly coned to
facilitate the insertion of the brass wire D, and it must be exactly in
the axis of F M. A guide B sliding on two rods _c_, _c_, is traversed
by the rod D which can be clamped in it by the screw _a_.
By pushing D against the screw-plate at the same time that the handle
N is rotated, a thread will be traced on it and it will emerge at _k_.
When B has advanced to the point _m_, the screw _a_ is released, B is
drawn back, and _a_ again clamped.
[Illustration: _Fig. 183._]
When a long screw, such as X _x_ has to be tapped, the screw-plate
is fixed at _m_, and the guide B is fastened on to the portion X. Of
course the hole in the screw-plate must always be abundantly provided
with oil.
If the screw-plate F is replaced by a plate perforated with a round
or square hole, a drill, broach or tap may be substituted for _k_,
being clamped by the screw _h_, and the tool is at once available for
drilling, broaching or tapping any given hole.
RAPID MODE OF MAKING A SCREW.
=390.= The methods ordinarily adopted by watchmakers are too well
known to need description; we will therefore at once proceed to give a
special plan recommended by M. Vissiere.
An eccentric poppet-head with boring-plate, Fig. 185, is fitted to the
bed of the lathe, the eccentricity being such that the axis of the
centers is at the point _a_ on the circumference of the circle _a y_.
The conical hole, having a center at _a_, is cut away towards the rim
of the plate to the degree indicated in the figure, and its center is
so placed that the vertical line _f_ and the radius _d_ are inclined at
120°. The position of the T-rest is shown at _s_, and by bringing it
into actual contact with the disc the steadiness of both is increased.
The fixed headstock of the lathe is provided with a runner of the form
B, Fig. 184, terminating in a point _m_ at one end and a hollow cone or
funnel _n_ at the other end.
Having filed the ends of a rod T, of any required diameter, square
and fitted a ferrule, support it between the two cones, _a_ of the
boring-plate and _n_ of the runner. Near the end _a_ cut a hollow _r_
sufficiently small to allow the stem to pass through the notch in the
hole _a_, Fig. 185. After passing it through, the rod will be supported
as shown at H, Fig. 184, so that the rim _e i_ rests against the cone.
[Illustration: _Fig. 184._]
[Illustration: _Fig. 185._]
Further explanation is hardly necessary; after removing the portion _c
g_ with a graver, turn down to a point _p_. When making a screw, turn
out a second hollow _o o′_; it then only remains to turn off the disc
at the extremity, and the screw will be roughed out of the form _c p g
v_.
If it is preferred to work with a point at the left-hand end of B,
remove the rod after the point _v_ has been turned, replace _m_ B _n_
by a common runner, reverse B, and recommence the operation.
It would be difficult to devise a method for roughing out a screw
and making a point that would be more expeditious than the one here
described.
SCREW-HEAD TOOLS.
=391.= These are of various kinds: some work by hand and others by a
bow. The jaws are brought together sometimes by a sliding ring, and at
others by a milled head placed between them and rigidly attached to a
pin tapped with right and left-handed threads that engage in the jaws.
But neither of these plans is good; the screws are not held firmly and
they are rarely well centered; owing to the slight displacements of the
jaws.
[Illustration: _Fig. 186._]
A better plan is to arrange, either in the lathe or in the jaws of the
screw-head tool (when driven by a bow), a series of chucks of the form
shown at T, Fig. 186. They are easily made and tapped, the hole _i_
serving to remove the metal from the inner end of the hole that has
to be tapped; such chucks occupy very little space, and, if numbered
to correspond with the size of screw, any chuck required can be found
without trouble. If the hole becomes too large owing to frequent use,
a larger size of tap can be passed through the hole and its number
changed.
=392.= A set of such chucks is almost indispensable at the present day
to the watchmaker who wishes to repair watches well; for he rarely
makes his own screws, as they are to be obtained well made and very
cheap at the material dealers, whereby a great saving of time is
effected. But their heads are seldom of the proper size to fit the
original sinks, and by being provided with such a series of chucks the
watchmaker can at once overcome this difficulty, as he can turn the
heads down with a graver.
=393.= R, Fig. 187, is an arbor for a screw-head tool that is driven by
a bow, and is adapted to receive such chucks, or it can be used in an
ordinary lathe, _d_ being supported on a pointed center, and _g_ in a
boring-plate, Fig. 188, or in a cone-plate center.
=394.= In this form of screw-head tool the portion A is sometimes
perfectly cylindrical, so that the piece V can slide on to it, being
clamped by the screw _b_.
This tube V is cut away through about half its length with a notch, as
indicated in the figure; bent pieces of hardened steel _c_ and _n_ are
screwed to either side of the notch. Screws, _h_ and _f_, provided with
lock-nuts, determine the distance between these plates, and when V is
in position on A the ends of _c_, _n_, will rest on the screw-head,
leaving just sufficient space between them for inserting the file that
cuts the slit.
[Illustration: _Fig. 187._]
Hard steel caps of the form shown at M may also be fitted to A, a notch
being cut in them to receive the screw _b_. These will be found useful
as guides for filing or polishing screw-heads, or the ends of arbors
flat, reducing the heads of several screws to the same height, etc.
[Illustration: _Fig. 188._]
=395.= The tool for forming the U-spaces in a cylinder escape-wheel can
be easily be converted into a screw-head tool with laps. A glance at
Fig. 189 will at once make this evident. A number of chucks are adapted
to the arbor A, and in the tube _c c_ either a T-rest or a spindle
carrying a lap is fixed.
It will also serve as a tool for drilling; a drill-chuck with drill,
_f_, being adapted to A, and the object to be perforated at _b_
resting against a plate that projects at right angles from a slide _d
d_, which may be advanced by a screw _g_.
=396.= The modern watchmaker has so little call to cut screws that it
does not pay him to purchase a screw-cutting lathe; for a very small
sum he can have screws of any thread or diameter cut by those who make
a specialty of such work, always provided that he cannot find what is
wanted in the material stores. The same thing also applies to fuzees.
[Illustration: _Fig. 189._]
TOOLS FOR CUTTING AND ROUNDING-UP THE TEETH OF WHEELS.
WHEEL-CUTTING ENGINE.
=397.= The machine for dividing the circumference of a wheel, termed
the wheel-cutting engine, and one form of which is shown in Fig. 190,
is well known to nearly all workmen. The wheel is fixed to a chuck at B
by wax or screws, or by the pressure of a hollow cone or “sugar loaf”
of steel, to the apex of which pressure is applied by the arm D, or in
other ways. The wheel may be centered either by a pump-center within
the chuck or by an appliance such as is shown in Fig. 191, except that
the arm _b_ is curved and its index much longer. This little addition
may be fixed to the frame of the engine in any convenient position.
[Illustration: _Fig. 190._]
The chuck B that carries the wheel is rigidly connected with a large
brass plate A A, on which are concentric circles of divisions, and the
whole can be maintained stationary by setting the point of the index C
C in any desired hole on the division-plate. The cutter is carried on
an arbor (shown separate at L) between horizontal bearings in the frame
J, and is caused to revolve by means of the pulley K. The several parts
lettered E, F, G, H, are for bringing the cutter against the wheel and
modifying the direction in which it moves, so that the machine can
cut straight or inclined teeth, bevel or crown wheels, etc. It should
be added that the engine here represented is more complex than those
ordinarily used for cutting watch wheels, although the principle on
which it acts is the same.
The teeth may be cut by circular cutters of the nature of files, by a
small straight cutter, similar to those used in a slide-rest projecting
from a rotating axis, or by several such cutters mounted on a disc
which is caused to rotate. For the sake of distinction it will be well
to refer to the first of these as _file_ or _mill cutters_, while the
second and third may be termed respectively _single_ and _multiple
blade_ or _composite cutters_.
[Illustration: _Fig. 191._]
Watchmakers rarely possess a sufficiently large assortment of
file-cutters for making all the various forms of teeth that are met
with in horology; but this deficiency can be supplied by making them
for themselves to any required pattern in the manner subsequently
described.
=398.= _Observations._ The wheel-cutting engine in which the plate
is caused to rotate by means of a tangent screw is usually the most
accurate. If the pitch of the screw is fine it will give all the
subdivisions of a circle that are required for ordinary work, but it is
essential that a good form of counter be attached to the screw, and a
certain amount of calculation is always needful.
The engine that has a division-plate with conical holes arranged
concentrically over its surface is simpler and better adapted for rapid
work. The larger this plate, the greater is its chance of being correct
and, at the same time, it affords room for a larger number of divisions.
It is preferable that the cutter frame rise and fall in a vertical
dovetail, for when the arbor is carried in an H shaped arm pivoted on
two screws, the teeth are always slightly dished. The entire apparatus
should be somewhat heavily constructed and supported on a solid bed; so
as to prevent the vibration of the cutter-arbor from being distributed
over the entire machine.
The highest numbers on the plate should be used whenever it is
possible, so as to diminish the error due to irregularities in the
sub-division. For example, in cutting a wheel of 30 teeth, use the 90
or 120 circles, taking every third or fourth hole.
These remarks will probably be sufficient to enable any watchmaker who
possesses a wheel-cutting engine to employ it with success; we will,
however, add the description of a few appliances or processes that have
a bearing on this question.
=399.= =To Divide a Wheel so that it has one Tooth more or less than
any given number on the Division-plate.= It is to be observed that
neither this nor the following method is mathematically exact, but
if it is practiced with care and the division-plate is of sufficient
diameter, the error may as a rule be neglected.
[Illustration: _Fig. 192._]
Let P, Fig. 192, be a division plate that has a 30 circle, but not one
of 29 or 31 divisions. Divide the circumference of a disc _d_, seen on
edge, into a large number of parts in the engine, 360 for example, and
fix it to the end of the index, at the same time attaching a finger,
_i_, to the support _s_. Now advance the screw of the index through a
distance corresponding to the angle _l_ P _k_ included between the two
successive points of the 30-division circle. To measure this distance
a pointer should be previously fixed to the frame to correspond with
the middle point of a hole in the circle under consideration, and the
motion should be arrested when it coincides with the next succeeding
hole. Assume that this amount of displacement has required three
complete turns of the screw; 1,080 divisions on the disc have thus
passed under the finger _i_. Dividing this number by 31, we obtain
34.83.
After observing the division on _d_ that coincides with the pointer
_i_, cut the first space of the wheel; then cause 34.83 divisions to
pass under _i_, in such a direction that the plate is drawn with the
arrow, and transfer the index to the next hole of the circle, rotating
this time opposite to the arrow; the second space can now be cut, and
so on.
With a view to diminish errors arising from the omission of fractions,
since 31 does not divide evenly into 360, a number of multiples of the
number 34.83 should be determined. Thus 4 times 34.83 is 139.32, so
that, when the fourth space is cut, the pointer _i_ must be at this
number of divisions from its initial position.
The index should be so situated that, when half the arc _l k_ has been
traversed, as explained above, _s a_ is at right angles to the radius
P _r_ of the division-plate. If it is desired to move _d_ in a reverse
direction, it must be moved backwards to a considerable distance and
then forward up to the required point so as to avoid error due to
backlash. The screw of the index should fit the support s firmly and
without any shake.
=400.= =To Cut a Wheel with any Given Number of Teeth.= When the given
number does not occur on the division plate, proceed as follows: Take a
strip of metal, for example a pliant piece of soft steel, and cut in it
a series of equal and equidistant notches as shown at B, Fig. 193. Cut
the band to such a length that it has the same number of pairs of teeth
and spaces as the wheel is required to have teeth. Now turn a lead disc
of a diameter that the strip of metal will exactly enclose; fix this
strip round the circumference with pins, screws, or in any convenient
manner, as is shown at C. We thus obtain a temporary division plate
which can replace the permanent one or be attached to its upper or
under surface, and, when an index has been adapted to it, the wheel can
be divided into the requisite number of parts.
[Illustration: _Fig. 193._]
When employing an engine the division plate of which is worked by a
tangent screw, the above affords an easy means of making the divided
head for the screw with any desired number of divisions.
=401.= With a view to insure accuracy, it is advisable to employ a disc
of large diameter as the errors of division are thereby rendered less
important and the metallic blade can be made to lie closer to the rim.
The blade is subdivided by a saw to which a guide is attached as
indicated at H, Fig. 193, or the saw can with advantage be replaced
by a file that only cuts on its edge and not on either face, or by a
pair of mills or revolving cutters united together as shown at S. The
following plan, however, appears to be more expeditious and to involve
less trouble to ensure accuracy.
[Illustration: _Fig. 194._]
A hole _a_, Fig. 194 is drilled in a metallic band by means of
a semi-cylindrical drill fixed in the chuck of a lathe or in a
wheel-cutting engine, etc. It will be convenient if the drill can be
set vertical. Beneath it is a brass bed-plate in which are fixed two
pins equal in diameter to the hole _a_; this hole having been placed
over one pin _b_, the band is held firmly against the other, while the
second hole is drilled. This is then transferred to the pin, and so on.
In the absence of a suitable tool, a well made measure can be employed
for marking a series of points with the aid of an eyeglass; the holes
are then drilled with the bow or in any other manner.
=402.= =To Cut a Wheel, Ratchet or Pinion on an Ordinary Lathe.= When
only a moderate degree of accuracy is required, the ordinary lathe can
be adapted for cutting the teeth of minute wheels, ratchets, pinions,
etc., by making the following appliance:
The piece B, Fig. 195, provided with a stud at _p_, slides on two
horizontal and parallel cylindrical rods fixed to the slide C, or it
may move in a dovetail. The cannon _d_, carrying a ferrule _k_ and a
file-cutter _f_, rotates on the foot at _p_ without shake; and the cord
of a wheel or bow passes round _k_.
[Illustration: _Fig. 195._]
R, the wheel to be cut, is supported between the runners, the divided
plate V, which may even be an old wheel with the required number of
teeth, being fixed to the axis of R. V is held stationary during the
operation of cutting, by the index _l_. The mode of action hardly
requires explanation: while _f_ is rotating, advance B until it is
arrested by the stop _t_; then draw B back, advance _l_ to the next
division on the plate, and so on.
=403.= We have said enough on this subject to enable any watchmaker
to make such a tool, modifying it or completing it according to his
requirements. We would only remark that: (1) If a cannon of the form
_d_ is used, the stud should be diminished in diameter at its middle
part for about three-quarters of its length, so that friction occurs
only at extremities; and (2) if a wheel is used to rotate _k_, there
should be an idle pulley at _m_ supported on a fixed arm independent of
B, either attached to the lathe-bed or bench, or fixed in the vise, so
that the ferrule _k_ can move backwards or forwards without altering
the tension of the cord, in the manner indicated at Y.
=404.= =Wheel-cutting Arbor-chucks.= These appliances are specially
useful in making wheels that are required to be rigorously true, such,
for example, as escape wheels. The form is represented in Fig. 196.
It is simply the arbor of an ordinary lathe, formed in two pieces, _b
a_ and _b c_, the body _b d_ being very accurately fitted into the
conical hole in the plate of the wheel-cutting engine. If now a wheel
is fixed with wax on the extremity _z_ and turned in the lathe to the
required form, it is only necessary to unscrew _b c_ and introduce _b
d_ into the socket of the wheel-cutting engine; then having cut the
teeth, the piece _b c_ is replaced, and the whole is set in the lathe,
if required to test its truth, without the wheel having been displaced
from the chuck.
[Illustration: _Fig. 196._]
It will, of course, be evident that the two parts must be accurately
fitted together; the tapped hole and the screw must be true with the
axis. M. Millot, with whom we have seen this form of arbor in use, has
not been able to detect any eccentricity, although he often employs
them.
=405.= They might be formed in one piece, as _a d b_, with a point at
_p_. A boxwood ferrule is then fitted onto the portion _b d_, where it
is clamped by two screws, and these can be released when it is desired
to insert the chuck into the wheel-cutting engine. The points of these
screws should be received in recesses in order to avoid the production
of any roughness on the surface of _b d_.
Wheel-cutting engines have been made to receive these arbor-chucks
without removing the pulley. The point _c_ is placed in a hole and the
upper end is enclosed in a collar, which is tightened by means of a
screw.
The arbor used by M. Millot had a lantern chuck, and this is very
convenient in making objects that require to be measured during the
progress of the work.
=406.= =Modification of the Ordinary Arrangement for Holding the Wheel
While Cutting.= In the wheel-cutting engine as usually met with, the
wheel (when not mounted on an axis) is held against the chuck by a
hollow steel cone, on which presses an arm that slides on a vertical
pillar and can be clamped in any position. The hole at the end of this
arm does not always, therefore, correspond with the point of the cone,
and, as a consequence, the wheel often gets displaced during cutting.
This inconvenience can be avoided by adopting the following device,
which we have seen in use with several watchmakers.
[Illustration: _Fig. 197._]
The pillar with its sliding arm is replaced by an iron or steel piece
of the form G, Fig. 197. The point _a_ is received by the central
hole at the lower end of the division-plate axis, while the screw
_b_ presses on the point of the cone, clamping it firmly. Further
explanation seems unnecessary; we would only add that the piece G must
be made strong and perfectly rigid.
CUTTERS FOR FORMING THE TEETH OF BRASS WHEELS.
=407.= For making the teeth of the wheels of a train, a special form
of cutter, set to revolve on an axis, is employed, and it may be
constructed on either of three distinct systems.
[Illustration: _Fig. 198._]
[Illustration: _Fig. 199._]
(1) A single cutter mounted on an arbor, as at A, B, Figs. 198 and 199;
this may be termed a _single cutter_.
(2) A circular cutter, formed of a series of such single cutters, which
will be termed a _multiple blade_ or _composite cutter_. Two specimens
are shown at F, J, Fig. 200.
[Illustration: _Fig. 200._]
(3) The pinion, or steel wheel cutter or mill, formed of a single piece
of metal, as seen in Figs. 201, 202 and 203. These may be described as
_mill_ or _file cutters_.
=408.= =To Make a Single Cutter.= The form shown at A, Fig. 198, is
roughed out to as nearly as possible the required form in good steel.
Some makers, possessed of exceptional skill, make them entirely by
hand, and they make very beautiful teeth by this means; but as a rule
watchmakers cannot look for such success, so that it is better to
complete the formation of the cutter in a specially arranged tool.
[Illustration: _Fig. 201._]
[Illustration: _Fig. 202._]
The two sides may be made in the wheel-cutting engine, with the same
mill cutter, which is inclined when used to undercut the acting edge;
but this operation is not as easy as it appears at first sight, and the
watchmaker will find it to his advantage to make the following device:
[Illustration: _Fig. 203._]
A spindle, _b d_, Fig. 204, supported between the runners, _t_, _v_,
serves as an axis for the arm _f g h_, which is bent at _g_ so as to
afford a support to a conical cutter _a_, driven on the ferrule _c_.
The descent of this arm is limited by an adjustable stop, fixed to the
bed of the turns.
Having removed the T-rest, replace it by the rod N, to which the cutter
is clamped by a screw _k_, after being roughed out so as to reduce the
work required of the cutter.
Place N so that the conical cutter occupies the position indicated at
_z_, and, if a slight pressure be applied at _h_ while _a_ is caused
to revolve, both the straight and curved portion of the side will be
formed, and the side will, at the same time, be bevelled to an angle
corresponding with that of the cone. The curved portion of the side
will be more or less undercut, according as the arm _h_ is depressed
below the horizontal plane passing through the axis of the lathe. The
opposite side is formed by inverting the piece _f g h_.
[Illustration: _Fig. 204._]
In smoothing or polishing it is only requisite to replace the cutter by
a smooth conical roller, and to work as before.
=409.= The cutter is sometimes fixed in the arbor as shown in Fig. 198.
The arbor itself is thick and perforated with a round hole in which the
tail of the cutter accurately fits, a slight pressure applied by the
screw _m_ being sufficient to make it steady.
For cutting the escape-wheels of clocks the arbor should have a
velocity of about 200 turns a second.
M. Peupin, a skilful watchmaker who adopts the practice here given,
having observed that with a sharp cutting edge he did not obtain a
sufficiently smooth surface, succeeded in obviating the difficulty by
drawing a polisher with rouge along the cutting edge, maintaining it at
right angles to the plane of the cutter. This operation, if carefully
executed, will serve to remove the feather-edge, to make the edge
even and yet not dull, and to secure a highly polished cut surface.
The sides of the teeth will present a proportionately better surface,
according as the portion _c a_ (M, Fig. 198,) approximates towards the
dotted line _c d_.
His escape-wheel teeth are cut in successive stages. The last stroke of
the cutter is given by advancing it against the side of the wheel, so
that the cutter axis remains in the plane of the wheel.
=410.= =Triangular Cutters.= When a cylindrical or conical mill is
not available for finishing and sloping the sides of a cutter, it may
be replaced by a triangular cutter (T or C, Fig. 205,) and when the
application of much force is required there may be a pointed bearing;
but this is seldom necessary.
[Illustration: _Fig. 205._]
If carefully hardened and set, such a cutter gives a clean cut; of
course it will not act for as long a period as the conical form above
described, but this is of comparatively little importance, since the
blank cutters are always roughed out previously to nearly the requisite
shape.
=411.= =To Make Several Cutters at Once.= By adopting the following
method, it is possible to make several such cutters in one operation.
Turn a steel disc of the form of an ordinary mill cutter, as shown at
_l p_, Fig. 200. To finish it, giving the same curvature to the two
sides, take a piece of steel, C, and shape the corner _r_ to exactly
correspond with the side of the point or ogive of a tooth, bevelling
it so as to give a cutting edge at the upper surface; then harden and
smooth it with care. Having fixed it in position in the tool that
carries the arbor _a_ and the roughed out disc (whether this be the
lathe, wheel or pinion-cutting engine, or a special device) in the
required position, one side of the disc may be finished. The arbor _a_
is then reversed and the other side finished in the same manner, so
that both sides have the same curvature in opposite directions.
Of course the tool C may be advanced against _l p_, either sideways
from _r_ towards _l_, or radially in the direction _l p_, as is most
convenient. Or the tool might remain fixed and the disc advance against
it radially or laterally.
The traverse slide in a lathe is usually provided with a stop; it
would then be very easy to form one side of the disc in such a tool,
afterwards reversing the arbor and forming the other side.
If a very good cutting edge is desired, the sides should be smoothed
and, when the disc is completed, it may be divided into pieces
similar to B, Fig. 199, each of which will serve as a cutter. It will
be noticed that the acting edge is not undercut behind; it is thus
necessary to slope the cutter a little as shown at B, as otherwise the
rim will choke in the spaces of the wheel, straining it without cutting.
=412.= =Composite Cutter Formed of a Succession Of Single Cutters.= By
mounting a series of identical single cutters round the circumference
of a disc, a circular cutter can be formed in the manner indicated
in Fig. 206. The upper portion represents the arrangement of the
pieces while they are being turned, and the lower portion shows
their positions when the cutter is ready to be used. M. A. Croutte,
to whom we are indebted for several of the details here given, was
much surprised that this form of cutter is not better known, since it
possesses certain special advantages; we will summarize his remarks on
the subject.
[Illustration: _Fig. 206._]
The separate cutters _b_, _g_, etc., Fig. 206, are not undercut from
the acting edge backward; they are merely reversed, so that this
acting edge is towards the front, in other words it lies along the
radius. These separate pieces possess a special advantage in that they
can be used until the steel is quite worn out by the setting; in this
respect differing from the undercut cutters, for they are not altered
either in form or thickness by setting.
As a set-off against this important advantage, they are characterized
by the inconvenience of requiring that the two sides of the blade be
exactly in a plane at right angles to the axis, and that the slide
carrying the cutter-arbor shall move in a direction parallel to this
plane. And even when this double condition is satisfied, there will
be friction of the two sides above the dotted line _i j_, Fig. 199,
against the sides of the teeth; and if the above named conditions are
not satisfied, the cutter, being presented edgeways, will be choked
with brass, and the results will be unsatisfactory.
=413.= In order to ascertain whether such a fault exists, it is only
necessary to notice whether the cutter becomes brass-colored on one
side towards the point, and on the other more inwards, and the sides of
the teeth exhibit striæ or scores in opposite directions, as indicated
at E, Fig. 207. The white strip, 1, 1, corresponds to the bottom of a
space between two teeth; 2, 2, and 3, 3, the two sides of this space,
spread out like an open book.
[Illustration: _Fig. 207._]
By examining the marks with care, and noticing the direction in which
they are inclined, it will be possible to ascertain both whether the
separate cutters are out of place, and in which direction the arbor
should be moved in order to correct any error.
We must, then, repeat that all the cutters must satisfy this condition,
because if only one is wrong it will produce the scores here referred
to.
The necessity of these precautions in the use of such a composite
cutter, and the fact that the friction of the portion above the line _i
j_, Fig. 199, renders it difficult to obtain a polished cut (which is
essential for such delicate depths as those of watches), have doubtless
prevented its use becoming general. For work that is somewhat larger
or rough, it will be found to give satisfactory results and will last
longer than a single cutter. A lubricant, such as glycerine or oil,
should be applied to it.
=414.= =Composite Cutters with the Cutting Edges Undercut.= An old
Paris clockmaker, Brisson, used a cutter of the form F, Fig. 200, for
the teeth of his wheels. He undercut the two sides of the blades by
means of a small special tool. Strictly speaking, the operation can be
performed by hand.
In order to ensure that the curves that form the ogives of teeth are
alike on the two sides of a cutter, he made a series of templates or
standards of the form C, Fig. 206, in which were two holes, C and _c_,
of equal diameter. The upper one, which might be funnel-shaped so as to
give a cutting edge, was half cut away, and, after being hardened and
set, could be used to give a final stroke to the circumference of two
discs of equal diameter. These two discs, or one cut through a diameter
would suffice, having been brought by a file to the form H, and joined
as shown at _r s_, can be mounted eccentrically so as to present a
cutting edge to the roughed out cutter A; the two sides can thus be
made even. The disc may then be finished by cutting away the metal so
as to give the form shown at F, Fig. 200.
By the aid of the standards he could easily reproduce the same forms of
teeth when required.
Fig. 200 comprises, at J, a cutter for the teeth of watch wheels of
the form employed successfully by M. A. Phillippe. The figure will
explain itself.
We have known a Geneva wheel cutter who employed these composite
cutters with advantage in making duplex wheels. The principal
difficulty he experienced arose from the distortion of the metal in
hardening, because the acting portion naturally lengthened a little.
This form of composite cutter certainly demands careful workmanship,
but, if the construction, hardening and polishing are good, it will
produce fine work and will last a long time.
=415.= =General Observations on Cutting the Teeth of Brass Wheels with
a Single or Compound Cutter.= High-class English watches, the movements
for which are made at Prescot, in Lancashire, have the wheel teeth made
by a composite cutter after the wheels are riveted to their pinions. We
have remarked that these watches make less noise when running down than
those in which the teeth have been formed with a mill or continuous
action cutter.
Success in forming teeth with cutters depends mainly on the securing of
a good form as regards the cutting edge, and on its being maintained
in good condition; on the steadiness of the entire machine, so as to
avoid vibration; on the weight of the wheel, and on the velocity of
the cutter being sufficient. A cutter ought never to assume a brassy
color except when it requires setting; if it does so, and this is not
the case, it proves that the metal is being strained or scraped with
friction. The velocity must be very considerable; greater with a single
cutter than with one that is composite. The velocity is limited by that
point at which the heat generated would cause the oil to evaporate,
soften the cutter, distort, and sometimes even displace, the wheel
operated on. The engagement of the cutter with the metal must be very
slight, and should never be increased suddenly.
Attempts have been made to enclose the arbor bearings in horn, but it
is liable to be distorted by the heat.
Before dividing the disc into cutters it is essential that the two
edges be carefully smoothed, and this without their being distorted.
This can easily be done in an old depthing tool, using an arrangement
like that shown in Fig. 208. The lap must be of hard wood, and its
right-hand corner rounded off so as to resemble the side of a tooth;
it is set to engage with one side of the cutter. We say the right-hand
corner, because a lateral pressure can then be applied. It is important
that the surface as left by the graver be clean cut, because if the
smoothing is too much prolonged, it will deform the cutter.
[Illustration: _Fig. 208._]
=416.= In some factories it is usual to use discs about 2½ inches in
diameter, for cutting the teeth of brass wheels in timepieces. The
single cutters are arranged round the circumference as follows: One
forms a space between two teeth; the one immediately preceding forms
the right-hand side of the ogive, and that which follows forms the
left-hand side. By adopting such an arrangement of separate cutters, if
their side that lies against the disc is slightly inclined backwards it
is no longer necessary to bevel off the cutting edge.
MILL CUTTERS FOR STEEL.
=417.= =Pinions, Keyless Wheels, Etc.= The cutters that last for the
longest period when used for cutting steel are those formed like a
file; but a watchmaker is not always in a position to make them
himself; we will, therefore, here only speak of those he can make,
the description of the first few being taken from a work by M. A.
Phillippe, of Geneva, _Les montres sans clefs_ (keyless watches).
=418.= =Cutter for Forming the Inclined Teeth of Winding Pinions.=
Fig. 201 shows at S a section along the axis of such a cutter, and at
P a side view. When it is believed to be of the required form, rest
a piece of lead on the T-rest of the lathe and press it against the
rotating disc. The impression made in the lead will afford a means of
ascertaining both whether the form is correct, and whether the surfaces
are smooth enough. This last point is important.
The cutting edges are formed by merely making a number of notches
around the circumference with a tool for cutting ratchet teeth. Then
advance this ratchet cutter so that it may engage with the convex edge
of the cutter operated upon, and against the back of the teeth of this
cutter; the ratchet cutter is then in a position to form a second face,
_o i_, by which the teeth of the cutter are undercut at the back, but
in such a manner that a small flat surface _o a_ is left in order to
retain the form. When a cutter made in this way will no longer bite, it
may be set by passing a hard slip of whetstone over the faces of the
teeth.
The ratchet cutter employed for making this cutter should never be
pressed against it heavily.
=419.= =Cutter for Ordinary Wheel Teeth.= We will now pass to the
consideration of cutters for forming teeth of the usual shape, of
intermediate steel wheels, set-hands wheels, pinions, etc. They may be
made as follows:
The rim is indented with small fine ratchet teeth, _b d_, Fig. 202. Any
burr produced on the sides is then carefully removed, and the cutter is
placed in the wheel-cutting engine, and notches, _c_, _c′_, _c′′_,
_c′′′_, etc., are formed on either side with a flat square-edged
cutter of such a thickness that the circumference is about equally
divided into hollows and prominences. It is important to note that the
right side of the teeth must be but slightly roughed, not more than
is required in order to raise a slight burr, all that is necessary to
form the cutting edge of this portion of the disc. In roughing these
sides, at least one out of every two of the small ratchet teeth on the
circumference should be left untouched, so as to ensure the required
thickness being maintained.
The cutter shown in section and elevation at S and P, Fig. 201, might
be cut on the side _n_ in the manner here explained, and the convex
portion _k_ might be indented with a fine ratchet-toothed cutter,
carried in the hinged cutter-frame of the wheel-cutting engine. The
degree of penetration may be determined by fixing an ivory disc against
the cutter and concentric with it, the two differing in diameter by
the depth the cuts are to be made. The teeth will be rather too square
towards the circumference, but their form can be carefully corrected
by hand. It is obvious that the very greatest caution is necessary in
hardening cutters.
=420.= =Rose-Cutters or Forming Pinion Cutters.= As the edges of
pinion cutters are rounded, they can be made in the manner suggested
by Thevenin. Supporting the roughed out cutter in the cutter-frame of
a wheel-cutting engine, he fitted in the axis of the division-plate
a kind of rose-cutter, N, Fig. 205. Its extremity, _n_, instead of
being flat, is hollowed out as indicated by the dotted line, and,
by presenting the cutting edge thus obtained endwise to the grooved
edge of the cutter, the correct form can be given to it. With a
mushroom-headed piece of steel and oilstone dust, the cutting edge of
the rose-cutter can be made more or less acute by modifying the angle
of this steel lap.
=421.= =Other Forms of Pinion Cutter.= When a cutter is merely required
for a special piece of work, and not for continuous use, it will often
be sufficient to make it as shown at A, Fig. 203; this is made by
grooving the disc (_c_), or forming its edges as at _d_, after which
a series of teeth are cut on the periphery with a revolving cutter,
taking care to leave no more burr on one side than on the other. Then
pass a smooth worn file (or a worn flat cutter) over the faces of the
teeth, applying oil at the same time, so as to produce a slight burr
on the edges; if the file is not allowed to bite too much and is well
managed, these minute ridges will be uniform. After hardening, the
cutter is ready for use.
If the faces were smoothed without subsequently applying the file, the
cutter would not bite; for its action depends on the slight projection
of metal that corresponds to the file-cuts. The cutter is nothing more
than a circular file, with two cuts per tooth. If the corners are
turned over evenly by means of a very hard burnisher the same effect
will be produced; but this operation is delicate, as the amount of
metal turned over must be the same in every case.
When a cutter does not bite, it must be softened and restored to its
initial condition.
=422.= Or the following method may be adopted when it is required to
make a cutter for a special purpose.
Proceed at first in the manner just described, but the periphery is
divided into a greater number of teeth with a flat cutter, and to a
rather greater depth, as at E, Fig. 203. Bend backward each tooth to
a distance equal to about half a space by any convenient method; for
example, by a lever resting at the bottom of each space and pressing
against the corner of the tooth, etc. Before bending the first tooth
introduce a piece of brass into the space behind it, of a thickness
equal to about half this space, so as to avoid bending too far; for
succeeding teeth the thickness must be about equal to a space; thus E
will become E′. An inspection of Fig. 203 will suffice to make the
operation evident; it amounts to bending back a series of separate
cutters. The disc is then hardened, and the faces of the teeth are
smoothed when they do not cut well; or merely smooth those that are the
first to become dull.
It is important to employ soft steel that has previously been well
annealed.
=423.= =Cutter for Making Square Spaces.= The teeth of such a cutter
can be easily formed with a file, as shown at L, Fig. 209, the edge of
the cutter, _f_, being passed backwards and forwards in the direction
of the arrows, applying considerable pressure and at the same time
slowly rolling _f_ around. Or the cutter may be set up on a short
arbor between the centers of the lathe; then pass the file backwards
and forwards across the edge until the cuts are formed, slowly
advancing the file in the meanwhile, so as to form the cuts around the
circumference without once raising the file. The cutter must then, of
course, be hardened.
[Illustration: _Fig. 209._]
=424.= =Forming Cutters with a Milling Tool.= The roughing of a
round-edged, or even of a square cutter, can also be effected with
the aid of a milling or “nurling” tool, proceeding in the same manner
as when milling the heads of screws, etc. The tool must be in good
condition, well provided with oil, and applied with considerable
pressure against very soft steel.
If necessary, the workman can make the mill for himself; it is shown at
M, Fig. 210. F shows the method of applying it to the cutter, and by
partly turning the mill (of course carried in a strong holder) around
its point of contact with the cutter, as indicated by the dotted lines,
the rim of F will be evenly roughed all around.
[Illustration: _Fig. 210._]
With good steel fairly satisfactory results are obtained in this
manner, but it is needless to observe that such cutters never bite as
well as those made in the usual manner.
=425.= =General Observations.= When cutters are used with steel they
must be driven at a less velocity than when cutting brass, and, as M.
A. Phillippe has observed, it is best to make the cutters for steel
of small diameter (about half an inch). They are more easily made and
are less distorted in the hardening. The velocity should diminish as
the diameter increases; for too great a velocity, especially when the
diameter is great, will dull the cutter and soften it, owing to the
heat produced.
Cutters must be turned very true: it is advisable to give them a last
stroke with the graver after they are fitted to the cutter-arbor that
will subsequently carry them.
When operating on steel it is best that the cutter frame of the
wheel-cutting engine be advanced by a screw so as to give it a slow
and easy motion; the results obtained are more satisfactory than when
it is advanced by hand or with a lever.
The following practice is not uncommon in factories when it is
desired to reproduce the exact form of a cutter. A notch is made
with the cutter in the edge of a piece of steel, X, Fig. 211, or a
series of notches _o o′_, etc., can be made by several cutters in the
circumference of a disc Z (same figure). After being hardened and
sharpened at the cutting edge, this disc is fixed at the center of
the division-plate of a wheel-cutting engine, and can then be used to
complete the grooving of any cutter that is set in position on the
cutter-arbor before hardening. The positions opposite to which the
notches were cut should be marked on the chuck, so that they may always
be set-square to the cutter.
[Illustration: _Fig. 211._]
=426.= Besides the forms of cutter above described for operating on
steel, we may mention that circular cutters may be used in which
all the notches around the circumference have been polished, thus
removing the burr, and preventing them from acting in the manner of a
file. But while, with the former kind, a somewhat rapid rotation is
necessary (although not so rapid as when cutting brass), with this
latter class the movement must be comparatively slow, and produced by
means of a hand-wheel; otherwise they will not cut, since the action
depends rather on the application of pressure, and resembles that of
a slide-rest cutter. The distance apart and width of the teeth of the
cutter, as well as their inclination, are of importance; if too far
apart they occasion a waste of time; if too large the machine will act
in a jerky manner, and when too narrow, an excessive pressure will be
needed in order to make the cutter bite the steel, which, it is to be
observed, must always be thoroughly annealed. The edge must be well
supplied with oil or soapy water when in action.
It is generally found best to advance the cutter against the edge of
the steel rather than across it.
TOOL FOR MAKING CUTTERS.
[Illustration: _Fig. 212._]
=427.= The instruments usually employed for making cutters for the
teeth of wheels and pinions are complicated and expensive, but the
author has designed one for his own use that is comparatively simple,
and can be made by any watchmaker. When the reader has grasped the
principle on which it acts he will be able, without difficulty, to
modify it so as to suit his requirements.
[Illustration: _Fig. 213._]
The frame B B _b_, Figs. 212 and 213, consists of the body of the tool,
B B, and a bar _b b_, which is attached to it by screws. Between the
two the division-plate P rotates on an axis E R. The end E of this axis
is formed as a chuck to receive the cutter _f_, which is clamped by a
screw _t_.
The support S _s_ J is held with friction in the lower part of this
frame, to carry the cutter-holder A L M. This cutter-holder is hinged
at _n_, so that it can receive a double motion, revolving about a
horizontal axis J, and about an inclined axis _n_.
The portion A L of the cutter-holder carries a perforated arbor _a c_,
with a ferrule _c_ that receives the tail of the small rose-cutter,
which will presently be described.
The end M rests against a guide G, held by a vane _o z_, which is
pivoted on a pillar _z_, and can be clamped in either of the directions
_z y_, _z x_, or by one of the screws _o_, _o_.
=428.= We will now consider the mode of action of the machine. Having
set the little arbor _c a_ in rotation, rest the end M of the arm
against the guide, and gradually advance the rose-cutter towards _f_;
the edge of _d_ will form the first notch in the grooved rim of the
cutter, and then will be raised from contact with it, owing to the
influence of the guide G. After moving the tool-holder back to its
initial position, advance the wheel P by a tooth, repeat the operation,
and so on.
=429.= If the cutter _f_ has to be notched on both sides, it must
be reversed on the chuck; turn the guide so as to point in the
direction _z x_, corresponding exactly to _z y_; then having set the
cutter-holder in the line _z h_, recommence operations. The two grooves
of the cutter will then necessarily be of similar form.
Teeth can be cut on the rim of _f_ by using a cutter of the form F,
Fig. 214, and holding M against a straight vertical guide.
With a given divided wheel, P, the teeth can be brought nearer together
by reducing the diameter of the cutter, and _vice versa_. It is well to
have some change wheels, but a better plan is to advance the division
plate by the aid of a tangent screw.
[Illustration: _Fig. 214._]
=430.= =To Make the Several Accessories.= _Form of the rose or
star-cutter._ The rose-cutter is formed of a mushroom-headed piece of
steel. Such a conical cutter is shown at C and R, Fig. 215, and at F,
Fig. 214. F and C are cut in the same way that conical cutters are
always made, and R is a small triangular prism that only cuts by its
three corners, _a_, _a_, _a_. As it is necessarily very small when
employed in making the cutters for watch pinions, it must, in such a
case, be supported at the neck by a little fork. Moreover, it must be
brought gradually against the steel to be operated upon, so as only to
engage a very little at a time. With a view to this, it is advisable
that the cutter-holder be advanced by a screw.
[Illustration: _Fig. 215._]
The star-cutter, shown at E, Fig. 216, is at times substituted for the
rose-cutter. It cuts with the corners _e_, _e_, etc., whether it be
going to the right or left indifferently. Or a triangular cutter like
T, Fig. 216, can be used in its place; but its angles are fewer and
less acute, so that they become dull more rapidly.
A few trials will be needed in order to determine the most convenient
rate of movement of the several parts; and the edge of the cutter _f_
must always be liberally supplied with oil. A little can may be so
arranged as to allow oil to fall drop by drop on to the cutter _d_,
Fig. 213.
[Illustration: _Fig. 216._]
=431.= _To make the guide._ Having mounted a plate, G, on the vane _o
z_, trace out the approximate form of the cutter with the point of
M; then cut off the superfluous metal, leaving a slight margin. This
excess is necessary because the curvature of the guide is not the same
as that of the cutter, for the indentations as they spread out from
the center (_t_) become gradually deeper. The guide should be tested
from time to time by operating on a blank brass disc fixed in place of
the cutter _f_ and the guide must be modified as experience shows to
be requisite. Its edge must be saddle-shaped so that the middle may
correspond exactly with the two dotted lines _z x_, _z y_, Fig. 213.
The position of the disc on the chuck _t_ must be brought to correspond
with the guide by carefully turned washers placed behind it.
=432.= _Driving attachment._ Fig. 217 shows one system that may be
adopted for connecting the ferrule C with a driving wheel. All that is
required is that the instrument be set in such a position that this
ferrule is placed as indicated in the figure with reference to the
distributor.
[Illustration: _Fig. 217._]
=433.= _Cutters of uneven thickness at the circumference._ It is
well-known that the edges of the cutters of rounding-up tools (=435=)
are made to taper off around the periphery. In order to indent such
a cutter, the guide must be mounted on a slide, so that it may be
gradually displaced while the operation is in progress, by an amount
previously determined upon.
The desired result can be obtained with sufficient accuracy by moving
the guide backwards by successive stages with a screw. The end _k_ of
the arm M, Fig. 213, is slightly tapered, so that a gradual depression
of M occurs, and each cut is deeper than that which preceded it.
[Illustration: _Fig. 218._]
=434.= _Modification in the construction._ This instrument may be
modified as follows: The disc to be operated upon is fitted to the
chuck of the division-plate D, Fig. 218, which is vertical, and the
entire system is capable of a movement of rotation round the axis of
the base P. Having set the disc in the plane _a b_, as shown in the
figure, clamp P; then, by traversing the cutter-holder, the teeth on
the side of the cutter towards _a b_ are made. This cutter frame having
now been removed, the base P is turned until the cutter is in the plane
_c n_, such that it is equally inclined on the opposite side of the
axis of the cutter frame; the teeth on that side may then be made, the
star-cutter being rotated in an opposite direction.
It is unnecessary to prolong our explanations of the instrument, as the
details already given will suffice for any intelligent workman.
TOOLS FOR CORRECTING THE FORM OF TEETH.
=435.= =Rounding-up Tools.= In Europe it is the practice, in making
watch wheels, to first notch the circumference by means of a flat
circular cutter in a wheel cutting engine, thus forming a number of
square teeth. They are subsequently rounded off to the usual form,
after the wheels are riveted to their pinions, in a special tool.
The apparatus employed for this purpose is termed a rounding up tool,
and its principal feature is a mill cutter F, Fig. 219, the portion
_a b_ of whose circumference is cut away and replaced by a guide _g
f_ made of steel spring, and so fixed as to coincide with the edge of
the cutter at _f_, and incline at _g_ in order to compel the cutter
to pass, at each rotation, into consecutive spaces of the wheel. Two
screws are provided, the one _f_ for setting the guide opposite the
edge of the cutter, and _g_ for placing the free end of the guide
opposite to a space.
This tool acts with great rapidity, a fact which has led to its being
very extensively used in the factories of France and Switzerland,
although the ordinary system of wheel cutting is preferred in England
for all the better class of work. For it should be noted that the
rounding up tool does not correct any errors that are due to bad
dividing; for example, if a wheel is found to have some of its teeth
larger than others, the tool can not be relied upon to correct them; on
the other hand, if a wheel is exactly divided it is improbable that the
employment of this tool will occasion irregularity.
[Illustration: _Fig. 219._]
The instrument we are discussing is, however, not much used by watch
repairers, although they are frequently called upon to touch up the
teeth of wheels, or to slightly reduce the diameters of their pitch
circles, operations which cannot be done by hand with much chance of
success. The limited use to which rounding-up tools have been put is
owing, in great part, to their high price, but cheaper tools on this
principle are now coming into use.
=436.= One of these is shown in Fig. 220. The wheel to be operated upon
is held against a small table at D between two vertical runners with
guard-pivot centers, and a cutter of the form shown at Fig. 219, is
fixed at C to a suitable chuck of a small lathe-head B; this is caused
to revolve by the hand-wheel A, a supplementary pulley K taking all
strain off the axis. The three milled-headed nuts seen at E, F, and G
are for adjusting the instrument; E for moving the lathe-head, so that
the cutter is in the same plane as the axis of the runners, a position
which is determined by the pointer I; F for advancing the wheel against
this cutter; and G for setting the plane of the wheel to pass through
the axis of the lathe-head as indicated by the index H. The instrument
is accompanied by a number of cutters to suit the various sizes of
teeth ordinarily met with, as well as of tables to support wheels of
different dimensions.
[Illustration: _Fig. 220._]
=437.= =Ingold Fraise or Cutter.= =Rounding-up Cones.= Either the
cutters devised by M. Ingold, or the rounding-up cones of M. Berlioz,
may be used for correcting the form of wheel teeth.
The Ingold fraise is a small steel cylinder perforated through the axis
so as to be mounted on an arbor, and having a number of longitudinal
notches on its circumference which makes it resemble a pinion, the
points of whose leaves have been ground off. The spaces of the fraise
are of the exact form required to be given to the teeth of the wheel,
and their surfaces are covered with fine file cuts so as to enable them
to remove metal from the wheel operated on.
Having mounted the arbor that carries it between two centers of a
depthing tool (made especially strong for the purpose), the wheel
is supported by its axis between the second pair of centers (with
guard-pivot points). If now the fraise be advanced by the screw until
its teeth engage with those of the wheel, and either be caused to
rotate, it will drive the other, and the fraise will thus shape the
teeth to a pre-determined form, the faces of each notch acting the part
of a minute file introduced between the teeth.
It will be observed that such an instrument is preferable to the
ordinary rounding-up tool, in that it may be relied upon to bring all
the teeth to the same shape, but, on the other hand, the latter tool
has an advantage in being available for slightly reducing the diameter
of a wheel when a depth is found to be too strong.
=438.= An objection has been urged against the Ingold fraises on the
ground of expense, as each dimension of tooth evidently requires a
cylinder specially adapted to it. This fact has led to the introduction
of “rounding-up cones” the invention of M. Berlioz, which act on
precisely the same principle, but are conical instead of cylindrical,
so that each fraise evidently takes the place of a number of Ingold
fraises. The total number being proportionately reduced. But great
dexterity is required in their use, so that they cannot be successfully
employed until after numerous trials.
=439.= =Exact Rounding-up Tool.= The author has devised an instrument
for giving to the teeth of wheels the exact form determined upon by
theory, but as it is of too elaborate a nature to come into general
use, we shall not do more than here refer to it. It is rather of
a nature to be used for scientific work, but might be found of
considerable value for accurately forming the blades of cutters that
are used in grooving the circular cutters employed for cutting the
teeth of wheels.
=440.= =To Round Up Teeth By Hand.= We have seen a country watchmaker
proceed somewhat as follows: His method was only effective, however,
for ensuring the verticality of the file, and did not maintain it
straight, nor could the curvature of all the teeth be relied upon to
be the same; these two conditions are satisfied by the system here
explained.
Formerly watchmakers possessed very considerable skill in this kind
of work, as the teeth were always formed by hand; but at the present
day, for want of practice, there is not one to be found in a hundred
competent to round up a wheel properly by hand alone. Recourse may be
had to the following expedient in an emergency; it necessitates the
construction of a small special tool, but this is so simple that it can
be made in a few hours by an apprentice.
=441.= Take a bar of metal or hard wood, made smooth on its faces and
square at the corners (R, Fig. 221), and adapt to it a slide, _c c_,
through the center of which a slot is cut to receive a clamping screw;
it slides between the four pins indicated in the figure. An arbor _a_
is supported by _c c_, parallel to R, having a plate at its end on
which a wheel to be operated on can be fixed by three screws and a
loose plate. It is centered by the circumference before clamping these
screws, rotating _a_ with a bow, and it may be well to place a piece of
tissue paper under and over the wheel in order to avoid scratches. V
is a tongue that can be introduced into the space between two teeth in
order to prevent the wheel from moving.
[Illustration: _Fig. 221._]
Two arms, _p p_, screwed to the bar R R, support the handle of the
rounding-up file _l_, which consists of a large cylinder _t_, _t_, that
slides in the arms _p_, _p_. The cylinder T must be exactly parallel
to the arbor _a_, and the longer it is the better. The file-holder
_s_, also shown detached at Y, Fig. 222, is merely driven onto the rod
_t_. The distance between the center of the axis _t_ and the face of
the file (_b b′_, Fig. 222) is equal to the radius of the circle that
embraces the external curves of two or more teeth, as will be explained.
[Illustration: _Fig. 222._]
The several parts being arranged as shown in Fig. 221, and the bar
clamped in a vise at E, it will be obvious that, if the wheel is
held in two fingers of the left-hand so as to prevent it from being
displaced, while the rod T is moved up and down, at the same time
rotating it with the right-hand, the curves of two teeth will be
adjusted to correspond with the arc _o o o_ (Z, Fig. 223), and, by
transferring the tongue V to the next succeeding space, the curve _i i i_
can be struck.
[Illustration: _Fig. 223._]
=442.= _Observations._ The curvature of the point of a tooth coincides
very closely with a circular arc described from a certain definite
center, and comprising either two or three teeth. In order to realize
these conditions in practice, the slide _c c_ is so adjusted that the
axis of T passes just within the circle that passes through _o_, _o_,
_o_, etc. (Z, Fig. 223), at which the points of the teeth commence; by
making trials with two or three file-holders that differ in regard to
the distance _b b′_ (Y, Fig. 223), it will be easy to select the most
suitable for producing the required curve. After operating on all the
teeth in succession, advance the wheel by means of the screw D, and
again work around the circumference, and so on. The progress of the
work should be frequently examined with the glass.
It is possible to dispense with the tongue V, and to merely steady the
wheel by hand; the work is thus done more rapidly, but must be examined
with very great care.
We would insist that the lengths of the two axes are an element of
success. In operating on watch wheels T should not be less than six
inches long.
By suppressing the tongue the motion of the two axes may be
co-ordinated so as to form any theoretical curve; This is the case
in the exact rounding-up tool already referred to, but it of course
renders the instrument more complicated.
=443.= =To Ease a Train of Wheels.= In very many of the cheaper watches
and timepieces now met with in commerce the teeth are rough and badly
cut, and the pinions but little polished, so that watchmakers are
constantly complaining of the difficulty of securing even a moderately
good depth. In such cases they have a simple method to adopt in
addition to those already referred to, namely, to polish the teeth with
a piece of charcoal.
A piece of smooth, even charcoal, with regular fibre, is moistened with
oil or water, and passed across the teeth individually; first with the
fibres lying in the direction of motion, and afterwards with them at
right angles to that direction.
If the charcoal is carefully selected and lightly applied for a
sufficient length of time and no more, the ogives will be found to be
nicely smoothed, and the depth will run far more easily than it did
previously. It is dangerous to use quick-cutting charcoal, as it is apt
to deform the teeth.
Smoothing with a brush charged with charcoal powder cannot be regarded
as anything more than cleaning; if the action is too much prolonged the
form of the teeth will be spoilt.
TO TEST THE ACCURACY OF CERTAIN TOOLS.
=444.= =Drilling Tool.= First center the runner in the lathe, and
ascertain that it is straight, cylindrical, and exactly centered; then
fit a ring to it so as to slide with friction to (temporarily) limit
the descent of this runner in the vertical stock of the tool.
After placing it in position, adapt to its lower end a collar, provided
with a long index of soft brass, which is bent so as almost to touch
the plate at its circumference. Rotate the runner and it will be shown
to be perpendicular to the plate if the point of the index remains at
the same distance from the plate.
As a confirmatory test the runner may be drawn up in the stock, and
the trial repeated after bending the index nearly to touch the plate.
=445.= =Uprighting Tool.= If the two stocks or tubes that receive the
runners are exactly in line, a runner should move easily through the
two at once.
Setting the points in contact in various positions in a vertical line,
observe whether they coincide, both when at rest and when rotated
together or independently.
First ascertain that the table is at right angles to the axis in the
manner already explained for the drilling tool, making the necessary
tests with the two runners independently. Then support between their
points a short arbor carrying a soft brass index. The position of the
lower runner being maintained constant by means of a collar as above
explained, rotate the upper one by hand; its friction will carry the
index and arbor around, the point of this latter being set close to the
plate. Repeat the operation by raising the pair of runners and bending
the index down to the same amount.
If in these various positions the point remains at the same distance
from the table, it affords evidence that the tool is accurate.
An uprighting tool consists of two parts: the table carrying the lower
stock, and the bridge that forms the upper stock. The base of this
latter is a ring turned flat and co-axial with the stock, and is fitted
accurately into a square groove surrounding the table, where it is
fixed by screws.
Any watchmaker understanding this mode of construction will easily
perceive when he has tested the tool in the manner above indicated,
both what are its faults and how far he can correct them.
=446.= The English uprighting and drilling tools, and some of foreign
construction, are combined on the same stand, and a good arrangement,
made by Boley, is shown in Fig. 224. It will be seen that the drill
can be set in motion by a hand or foot-wheel; the table is fixed in a
vise and provided with two dogs for clamping the object. The drilling
spindle is perforated throughout its length so that the drill can be
held by an American split chuck.
[Illustration: _Fig. 224._]
=447.= =Depthing Tool.= As the value of a depth depends essentially
on the overlapping of the teeth being the exact amount required by
theory, it is specially important that the tool used for determining
the distance between the centers of the wheels and pinions should be
of the utmost attainable accuracy.
First ascertain that the spindle which serves as an axis for the two
halves of the tool does not change position when they have been several
times separated and brought together. For, if this were to happen, and
a runner were uneven or the hinge not smoothed within, the parallelism
of the two pairs of runners would be impaired.
The runners must be of equal thickness throughout, and should pass with
ease from one head to that opposite. Their points and center holes
must be seen to be in good condition, and, on placing them in their
turns, they must be found to be both true and cylindrical. Having
restored them to their places with the points together, move the
pair lengthwise from one head to the other, examining the points in
successive positions to ascertain that they coincide accurately, both
when the runners are loose and when clamped. When the adjustment has
been carelessly done the runners will be found to bend under pressure,
causing the points to be displaced.
Having set two runners side by side and level, describe with them
circular arcs on a smooth piece of brass from centers previously
marked, first with the points just projecting from the heads and then
projecting more and more. These tests may be made both within and
without the tool; so that there will be four sets of tests in all.
It is very important in making the last-named trials, that the tool be
maintained at right angles to the plate on which the circular arcs are
traced; this condition can easily be satisfied by a special device,
or by merely causing the compass to slide along a set-square. It may
be added that the series of arcs should be drawn end to end, in order
that it may be easier to observe their agreement or difference when
examining with the glass.
=448.= When this series of tests has been gone through, and the points
have been examined so as to make sure that there is no burr which bends
over while tracing the arcs, it is possible to determine the value of
the tool; we know whether it is perfect or not, and what corrections
are required. As a rule there are two points mainly at fault; the
holes in the heads are not exactly continuations the one of the other,
so that they need to be broached out afresh and new runners have
to be made. A careful and intelligent workman who is provided with
suitable tools will be able, from the information given in this work,
to correct, or at least improve, a defective depthing tool; but, as a
rule, it will be better done by the maker.
PART V.
REPAIRING AND EXAMINING WATCHES.
METHOD.
=449.= Expedition and certainty in watchmaking and repairing are
primarily secured by proceeding on a definite system, both in details
of construction or repairing.
The best watchmakers, and practical men generally, take their work in a
certain order, from which any departure is exceptional. By this means
they avoid the necessity of doing work twice over and of frequently
taking up the same piece; a circumstance that often occurs with young
watchmakers, owing to forgetfulness or to a want of sequence in their
ideas.
They should from the first exercise themselves in working methodically
on a definite system.
It must, however, be understood that no method can be inflexible, nor
can it be equally advantageous for different individuals, because
men differ in regard to manual dexterity, goodness of eyesight and
of memory, power of associating their ideas, etc. A system that is
suitable to a person of unexcitable temperament will have to be
modified by one is oppositely disposed. Everyone will be able to decide
for himself as to the best system to adopt and the order in which to
take his daily work.
These preliminary observations appear necessary because the method
explained below of examining a Geneva watch has been regarded by some
as too long and minute. We would urge any young watchmaker that hears
such ideas advanced to assure himself that it is a mistake, because the
system here explained is only put forward subject to the modifications
that experience suggests; and it is to be observed that many of the
operations given can be performed more rapidly than they are described.
When a watchmaker experiences a great loss of time, does it not usually
arise from the fact that he is obliged to take a watch to pieces, or
nearly so, after its repairing and examination were thought to have
been completed; or when a watch that has been repaired is brought back
to be examined before the ordinary period of cleaning has elapsed?
Let him add together the numerous hours spent in this kind of thankless
work, let him sum up the worries experienced, and the discredit, etc.,
to which he has been subjected, and he will see that systematic work
would have saved him both loss of money and loss of credit.
EXTERNAL EXAMINATION OF THE WATCH.
=450.= In the following paragraphs, when the manner in which a given
fault manifests itself is not indicated at once, it should be sought
in the index of this volume, either under the name of the operation or
under that of the object to which it relates. The reader will see for
himself which passages refer exclusively to the English or American and
which to the Geneva watch.
=451.= =Case, Glass, Dial, Dome.= Glance at the case in order to
ascertain that it has not received a blow or been subjected to
pressure; that the joints and fly springs work well; and that the
hands in rotating touch neither the glass nor dial. By laying the
nail on the surface of the glass, it will be easy to see whether there
is sufficient freedom between the socket of the hand and the glass.
In case of doubt, place a small piece of paper on the hand, close
the bezel and tap the glass with the finger while the watch is in an
inclined position. If free, the paper will be displaced.
The set-hands square should be rounded at the end and a trifle below
the level of any accidental bending of the back of the watch, and the
dome must not press on the balance-cock wing or the central dust cap
(if present). The above remark also applies to the winding square of a
fusee watch.
There must also be sufficient freedom between the going-barrel teeth
and the banking-pin of the balance on the one hand, and the internal
rim of the case, the fly-springs, and the joints on the other.
Otherwise there is danger of contacts when the case is closed which
occasion irregularity and stoppage often difficult to detect.
=452.= The dome must be at a sufficient distance from all parts of the
movement, more especially the balance-cock. If there is any occasion
for doubt on this point put a thin layer of rouge on the parts that
are most prominent. Close the case and holding it in one hand to the
ear, apply a pressure at all parts of the back with a finger of the
other hand, listening attentively in order to ascertain whether the
vibrations are interfered with. If the interval is insufficient, a
trace of rouge will be found on the inside of the dome. In such a case,
if the dome cannot be raised nor hollowed slightly in the lathe (when
formed of metal), lower as far as possible the index work and the
balance-cock wing and fix in the plate, close to the balance, one or
two screws with mushroom heads that will serve to raise the dome.
Ascertain that the hands stand sufficiently far apart; that the hour
hand does not rub against the hole in the dial; and that the minute
hand does not come nearer to the dial in one place than in another, a
fault which may arise either from the dial not being flat or from the
center-wheel being badly planted.
Remove the movement from its case, after making sure that it is held
steadily by the locking screws; take off the hands, and see that the
hour wheel has the right amount of play; this freedom may be diminished
if required by laying on the wheel small discs of tinsel cut out with a
punch. If the dial presses against any part of the movement, or is not
flat or comes so near to any of the pivot-holes as to draw off the oil,
it must be ground away until a sufficient amount of freedom is obtained.
TO EXAMINE A GENEVA MOVEMENT.
=453.= Although the following remarks refer in the main to foreign
watches with a Lepine movement, very many are also applicable to the
English and American watches; further observations specially bearing on
them will be found in articles =477-80=.
=454.= =The Motion Work and Hands.= Rotate the wheels connecting the
hour and minute-hands by the aid of a key and a glance will suffice
to show whether the several depths, which should be light, are
satisfactory. The wheels should not rub against one another, the plate,
barrel, or stopwork. The barrel should have been previously examined to
ascertain that it is not inclined to one side, as if it were, an error
would probably be made in estimating the degree of freedom.
The set-hands arbor (the square of which should be a trifle smaller
than that of the barrel-arbor) must turn rather stiffly in the center
pinion, and the cannon pinion must be held on the arbor sufficiently
tight to avoid all chance of its rising and so becoming loose; for
this would alter the play of the hands and motion work. If any fault
is found in the adjustment correct it at once, so as to avoid doing so
after the movement has been cleaned.
If it has not been already done, slightly round the lower end of cannon
pinion and the steel shield, care being taken to avoid forming a burr
on the pinion leaves. These two pieces ought to rest on the ends of the
center pinion pivots, and at the same time be some distance removed
from the plate and bar respectively.
=455.= =Freedom and Endshake.= Observe that there is sufficient
clearance between the plate and barrel; the barrel and center-wheel;
the several wheels in succession both between themselves, their cocks,
and sinks; between the balance on the one hand and its cock, the
center-wheel, fourth wheel cock, the balance-spring coils and stud on
the other. The fourth wheel is frequently found to pass too near to the
jewel forming the lower pivot-hole of the escape-wheel.
The end-shake of the wheels may be tested by taking hold of an arm of
each with tweezers and lifting it. This may also be done in the case of
the escape-wheel, but, when the cock is slight, it will be sufficient
to press gently upon it with a pegwood stick, then releasing it, and
observing the apparent increase in the length of pivot. At the same
time ascertain that the width and height of the passage in the cock
is enough to allow the teeth, when carrying oil, to pass with the
requisite freedom.
Holding the watch on a level with the eyes, lightly raise the balance
with a pegwood point several times, each time allowing it to fall.
The variation observed in the space between the collet and cock will
indicate the end-shake of the balance-staff.
=456.= =Action of the Escapement.= The side play of the balance pivots
in their holes can be easily estimated by touch, or this may be done
by the eye, attentively watching the upper pivot through the end-stone
with a powerful glass, while the watch lies flat and the lower pivot
in the same manner with the watch inverted. If the end-stones are not
clear enough, although such a case is rare, remove first one end-stone
and examine the pivot; then replace it and remove the other.
It should be possible to rotate the balance until the banking pin comes
against its stop, without causing the escape wheel to recoil at all, or
allowing a tooth to catch outside the cylinder behind the small lip.
The banking-pin sometimes passes too near to the fourth wheel staff.
The =U=-arms should rest nearly in the middle of the banking slot of
the cylinder: they should be as far from the upper as from the under
edge of this slot, so that the end-shakes may have free play in all
positions of the watch.
Ascertain that the balance-spring is flat; that it coils and uncoils
regularly without constraint; that it does not touch the center wheel,
the stud, or the inner curb-pin (with its second coil). The rapid
examination of the escapement may now be regarded as completed if the
watch in hand is merely being cleaned after having previously gone well.
But if engaged on a watch that has not gone well previously, or if
examining a new one, the action of the escapement must be thoroughly
tested.
=457.= =Visible Depths.= While the train is in motion through the
force of the mainspring or the pressure of a finger against the barrel
teeth, examine with a glass all the depths that are visible. That of
the escapement, for example, can be easily seen through the jeweled
pivot-hole when this is flat, the watch being laid horizontal and a
powerful glass used. When the action cannot be seen in this manner with
sufficient distinctness, hold the watch up against the light and look
through it. Depths that cannot be clearly seen, or about which any
doubt exists, must be subsequently verified by touch. (=458.=)
If examining a new watch, it may be found necessary to form inclined
notches at the edge of the cocks or near the center hole of the
plate so to see the action of the depths. But it is important that
the settings of the jewels are not disturbed, and indeed that enough
metal is left around these holes to admit of their being re-bushed if
necessary.
=458.= =Invisible and Doubtful Depths.= These must be tested by touch,
and the requisite corrections applied after having re-polished the
pivots, etc., as may be necessary. We would observe that holes a trifle
large are less inconvenient than those which afford too little play;
providing the depths are in good condition.
=459.= =Length of Balance Pivots: Centering the Balance-Spring.= Remove
the end-stone from the chariot and see that the pivot projects enough
beyond the pivot-hole when the plate is inverted. Then remove the cock
and detach it from the balance. Take off the balance-spring with its
collet from this latter and place it on the cock inverted, so as to see
whether the collet is central when the outer coil is midway between
the curb-pins. Remove the cock end-stone and end-stone cap, place the
top balance pivot in its hole and see that it projects a little beyond
the pivot-hole.
Place the balance in the figure-of-=8= calliper to test its truth, and,
at the same time, to see that it is sufficiently in poise; it must be
remembered, however, that the balance is sometimes put out of poise
intentionally.
=460.= =Play of Train-Wheel Pivots.= Allow the train to run down: if it
does so noisily or by jerks, it may be assumed that some of the depths
are bad in consequence either of the teeth being badly formed, or the
holes too large, etc. To test the latter point, cause the wheels to
revolve alternately in opposite directions by applying a finger to the
barrel or center-wheel teeth, at the same time noting the movement of
each pivot in turn in its hole; a little practice, comparing several
watches together, will soon enable the workman to judge whether the
play is correct. The running down of the train will also indicate
whether any pivots are bent. Now remove the barrel-bar with its several
attachments.
=461.= =Center-Wheel: Bad Uprighting.= Remove the third wheel, and, if
necessary, test the uprighting of the center-wheel by passing a round
broach or taper arbor through it, and setting the plate in rotation
about this axis, holding a card near the edge while doing so. This will
indicate at once whether the axis of the wheel is at right angles to
the plate.
When a marked deviation is detected, or the holes are found to be too
large, they must be re-bushed and uprighted again. When, however, the
error is but slight the axes may be set vertical by bending the steady
pins a little, in doing which proceed as follows:
Set the bar in its place alone, the screw or screws being a little
unscrewed, and rest the side of the bar opposite to that towards which
it is to be bent against a piece of brass held in the vise, and strike
the farther edge of the plate one or two sharp blows with a small
wooden mallet. Experience alone can teach the workman to proportion
the blow so as to obtain a given amount of deviation, and must enable
him to ascertain whether it is desirable or not to pass a broach
through the steady-pin holes before operating as above explained. Some
discretion is essential in practising the method.
It is important that the center pivots project beyond the holes in the
plate and bar. A circular recess is turned around the outer end of each
of these holes so as to form reservoirs for oil. Owing to the neglect
of these simple precautions, which are so easy to take, many watches,
especially those that are thin, come back for repair with their
center pivots in a bad state, because the oil could not be applied in
sufficient quantity, and has been drawn away by the cannon pinion or
the steel shield.
If the watch has a seconds hand, ascertain by means of the calliper
that its wheel is upright. Finally, examine each jewel to see that it
is neither cracked nor rough at the edges of the hole.
=462.= =The Barrel: to Take Down and Repair.= The side spring, which
must not be too strong, should reach with certainty to the bottom of
the spaces between the teeth of the ratchet, and this latter should
be held steadily in position by the cap. It is a good plan after
making the extensive repairs here spoken of to again test the barrel
and center pinion depth, either by touch of by drilling a hole for
observation.
The screw of the star-wheel must not project within the cover nor rub
against the dial; it must be reduced if either case presents itself.
The action of the stopwork must be well assured, especially when the
actual stop occurs. It is a good plan to, as it were, “round-up” the
star-wheel and finger-piece, with an emery stick, supporting them on
arbors. There must be no possibility of friction between the finger and
the bottom of its sink.
[Illustration: _Fig. 225._]
=463.= =To Test the Stopwork.= Take up the winding square of an arbor,
with the barrel, etc., in position, in a pair of sliding tongs or a
Birch key; hold the tongs between the last three fingers and the palm
of the left hand, the first finger and thumb being applied to the
circumference of the barrel so as to rotate it, first in one direction
and then in the other. During this movement, take a pegwood point in
the right-hand, and try to turn the star-wheel _against_ the direction
in which it would be impelled by the finger; the position is indicated
by B in Fig. 225. The tooth that is just going to engage with the
finger will thus be caused to take up the worst possible position for
being turned, and thus, if the action proves to be satisfactory for
each tooth, we may rest content as to the future; providing, of course,
that the engagement takes place square, and there is no tendency to
cause distortion of the metal. When the corner of C is stopped against
the convex tooth of the star-wheel, the finger should be free in a
space, and directed towards the center of A. By holding the sliding
tongs in a vise both hands can be kept at liberty.
For details in regard to the examination and repair of keyless
mechanism, see article =481=.
ACCESSORIES FOR BEGINNERS.
=464.= To facilitate the work by securing order in taking to pieces and
cleaning, preventing the screws from being mixed, etc., it is a good
practice to prepare beforehand one or more boards, in which grooves and
holes are made in positions to correspond with those of the several
pieces on the plate of the watch, as indicated by Fig. 226.
[Illustration: _Fig. 226._]
The round holes receive the cock and bar screws, which may be cleaned
while the other parts are in the benzine solution. (Two holes are shown
side by side for each bar and cock, so that the same plate will serve
for a large and small watch). The oval or circular hollows at _a_ and
around _m_ receive the cap screws, and _m_ the shield; _c_, _c_, _c_,
hold the screws of the side spring and star-wheel and the finger-piece
pin; _j_ is for the screws of the top end-stone, and _n_ for those of
the bottom end-stone, etc.
It may be well here to mention the very convenient divided boxes for
holding the several parts of a watch when taken to pieces that are in
general use by watchmakers. They measure about six inches by four, and
one inch in depth, thus being large enough to contain all the parts of
any ordinary watch.
At first every young watchmaker will find the advantage of noting on
paper, bearing the number of the watch, the successive operations that
have to be done. He will then merely have to strike them out one by one
as the work progresses. As he becomes more practiced he can dispense
with this auxiliary.
CLEANING THE WATCH.
=465.= Whatever system of cleaning is adopted it is essential that it
be concluded by passing a pegwood point into each of the holes.
Brilliancy is given to the surfaces of cleaned pieces by passing a
carefully kept fine brush over them. A brush that is greasy can only
be cleaned by soap and water, and a new brush is prepared for use by
passing an inclined cutting edge over the ends of its bristles so as
to taper them off to fine points, and to remove knots due either to
hard parts or to bristles becoming united. This preliminary treatment
is completed by charging the brush with French chalk, and rubbing it
vigorously on a dry crust of bread until the brush can be passed over
a gilded surface without scratching it. The bristles are maintained
in good condition by the same treatment. Billiard chalk is also very
effective for this purpose, and the greater number of cavities there
are in the crust the better it will act. A burnt bone is an excellent
substitute for the crust, and has the advantage of causing the brush to
impart a very brilliant appearance to objects to which it is applied.
=466.= =To Clean with a Brush.= This method is less used now than
formerly, as it can be adopted with safety with the old-fashioned
gilding, but is too severe for the thin galvanic coats that are applied
at the present day. It may, however, be resorted to for getting up the
surface of polished brass wheels, for example.
Put some French chalk or powdered sal-ammoniac (which can be bought
at a chemist’s) in pure alcohol. Shake the mixture, and with a fine
paint brush coat the object with a small quantity of it, subsequently
brushing the surface with a brush that is in very good condition.
Polished wheels may be made to present a very brilliant appearance
by this means, but their teeth and the leaves of pinions must be
afterwards carefully cleaned.
The French chalk and sal-ammoniac are all the more effective according
as they have remained a longer time in the alcohol; doubtless owing to
the fact that the hard grains met with in them are then more completely
dissolved.
=467.= =Soaping.= It is advisable to use a soap that quickly produces a
good lather; and the object is held in the hand and cleaned by rubbing
with a soft brush charged with this lather; then immerse first in clean
water, and subsequently in alcohol, moving it about in each: it may be
left for a few seconds in this latter, and, on being removed, is dried
with a fine linen rag or soft muslin. A stroke with a soft brush in
good condition will give brilliancy to the surface. As water sometimes
dissolves the soap very slowly, it is desirable that it be employed
warm. If about to soap polished wheels, the surface must be first got
up with a buffstick and rouge, or by brushing with sal-ammoniac.
The balance spring may be cleaned by laying it on a linen rag doubled,
and tapping it gently with a brush charged with lather; then dipping in
water and alcohol in succession.
The alcohol may be used hot or cold; its action is, however, more rapid
and effective in the former case. But there is no occasion to use hot
alcohol except when dealing with substances such as wax, that resist
its action.
=468.= =Essences and Benzine.= The employment of essences in cleaning
watches is becoming more general every day. They are to be obtained
at all material dealers, together with full instructions in regard to
their use. A few observations may nevertheless not be out of place here.
The objects are left in the solution for a few minutes in order to
allow all adhering matter to dissolve, but they must not remain too
long, as certain qualities of benzine, etc., are apt to leave stains.
Dry the pieces on removing them, and finish by passing over a fine
brush that has been charged with chalk and subsequently been rubbed on
a hard crust or burnt bone; as has already been observed, this will
produce a brilliant surface on either gilding or polished brass.
The following composition, the ingredients of which can be obtained
at any chemist’s, has been strongly recommended to us by a clever
watchmaker:
90 parts by weight of refined petroleum.
25 ” ” sulphuric ether.
The objects are immersed for several minutes; indeed, they may remain
for a longer period without danger, and on removal from the bath are
found to be clean and bright. It must not be forgotten that many of
these essences are liable to ignite with the mere proximity of a lamp.
PUTTING THE WATCH TOGETHER.
=469.= The three following rules must be observed in arranging a system
of putting the watch together: (1) avoid taking up the same piece two
or more times; (2) hold it lightly, as any pressure will produce a
mark; (3) keep it as short a time as possible in the fingers. Any linen
rags used must be free from fluff, but rags of all kinds should as far
as possible be replaced by certain kinds of tissue paper. The best
kind will be that which, while securing a given degree of pliability,
will best prevent heat and moisture from passing through. Blue-shaded
tissue paper should be avoided, as it is often found to encourage the
formation of rust on steel work.
=470.= The following order is adopted by some excellent watchmakers in
putting together the ordinary form of Geneva watch; it may be adopted
exactly or modified as experience dictates.
Commence by putting the several parts of the barrel together, attaching
it to the bar and observing the directions given farther on (=474=)
in regard to the distribution of oil. Owing to the position of the
stop-finger, it is sometimes found that the mainspring must be set up
either one-quarter or three-quarters of a turn. Very often one-quarter
is not sufficient, and in such cases it is necessary, before putting
together, to ascertain that the spring admits of at least 5 or 5¼
turns in the barrel. If it will not allow this amount, and yet has to
be set up three-quarters of a turn, too great a strain will come upon
the eye of the spring in winding. Fix the chariot with its end-stone on
the under side of the plate.
Replace the fourth wheel, making sure that it is free and has no more
than the requisite end-shake and is upright. Then the escape-wheel,
testing it in a similar manner. See that the teeth have sufficient
freedom on both sides of the cock passage, then make the two wheels run
together with a pair of tweezers of pegwood, in all positions of the
plate, to make sure of everything being free.
=471.= After attaching the index and end-stone to the balance-cock and
the balance-spring to the balance (observing that the center of the
stud is against the dot on the balance rim), place some oil in both
the balance pivot-holes (=476=); adjust the balance to the cock after
placing a drop of oil in the cylinder (though a much better plan is
that given in article =476=), and set in position on the plate. Some
workmen apply a drop of oil to the top of the escape-wheel pivot-hole
before setting the balance-cock in its place, but others prefer only to
add the oil after the escapement has been tested.
Placing a small piece of paper first between the balance and cock, and
then between the balance and plate, ascertain whether the escape-wheel
occupies its correct position in reference to the cylinder, in order
that the escapement may act properly. This test is especially necessary
in dealing with very thin watches or those in which the cylinder
banking slot is exceptionally narrow. The barrel bar is now fixed to
the plate.
=472.= Set the third wheel in its place, and lastly the center wheel,
after putting a little oil on the shoulder of its bottom pivot. Before
putting the bar over it, apply oil to the top pivot in a similar
manner; then screw it down. After this is done screw on the third wheel
cock.
Now apply a small quantity of oil to the two center pivots, and very
lightly to the others that have not already been oiled; give a turn
to the key and listen to the tick of the watch in all positions. This
should always be done before replacing it in the case.
After passing the slightly-oiled set-hands arbor through the center
pinion, and adapting the cannon pinion to its end, reverse the watch,
passing the end of the center arbor through a hole in the riveting
stake, so that the watch is supported on the end of the cannon pinion;
a light blow of the hammer on the square end of this arbor will then
suffice to drive the cannon pinion home. Some do this before replacing
the movement in its case, and some after.
Add a little oil to such pivots as have not already received enough,
and fix in their places the remaining parts of the motion work, the
dial and hands: the watch then only requires to be timed.
=473.= =Precautions to be Observed in Applying Oil.= The method of
distributing and applying the oil is of more importance than might be
thought, and has a very marked influence on both the time of going and
the rate.
Oil that is very fluid may be used for the escapement and fine pivots,
where only a small quantity is needed and the pressure is slight;
but it is not suitable in other places on account of its tendency to
spread, and thus leave the rubbing surfaces.
If too much oil is applied the effect is the same as if there had been
too little; it runs away, and only a minute quantity is left where it
is wanted.
=474.= _Barrel._ It is not enough to apply oil to the coils of the
spring; some must also be placed on the bottom of the barrel. Before
putting on the cover, moisten the shoulder of the arbor-nut that comes
in contact with it with oil; by doing so, when oil is applied to the
pivot, after the cover is in its place, this oil will be retained at
the center of the boss in the cover. Moreover, it will not then be
drawn away by the finger-piece, passing from this to the star-wheel.
The oil applied to the upper surface of the ratchet to reduce its
friction against the cap must not be in such quantity as to spread on
to the winding square. It is a good plan to round off the lower corner
of this cover.
=475.= _Center-wheel._ The observation made above in reference to the
oil applied to the barrel-cover may be repeated here. By proceeding as
explained in article =472=, and adopting the precautions mentioned at
the end of article =461=, it is possible to make sure of the pivots
lasting for a long period.
=476.= _Escapement pivots: Cylinder._ When the drop of oil is
introduced into the oil-cup of the balance pivot-hole, insert a very
fine pegwood point, so as to cause the descent of the oil; a small
additional quantity may then be applied. When this precaution is not
taken, it frequently happens that in inserting the balance pivot its
conical shoulder draws away some of the oil, and there is a deficiency
both in the hole and on the end-stone.
As has been already noticed (=471=), some workmen place a single
drop of oil within the cylinder, and when the escape-wheel advances
each tooth takes some up. This method is unsatisfactory, because the
earlier teeth receive such a quantity of oil that it runs down the
pillars, where it is useless and merely tends to increase the weight of
the wheel. A much better plan is to put a very small quantity in the
cylinder, and on the flat of each tooth or every second or third tooth.
It will thus be evenly distributed, and will not tend to flow away.
The escape-wheel pivots require but a small quantity of oil. It often
happens, however, that, owing to carelessness, the workman applies
too much, and it runs down to the pinion. The leaves will thus become
greasy and stick, while the pivots are running dry.
TO EXAMINE ENGLISH OR AMERICAN MOVEMENTS.
=477.= As has been already observed in article =453=, many of the
remarks made in speaking of the Geneva movement are equally applicable
to that of English or American construction, and any intelligent
watchmaker, on reading articles =450-463=, will be able to select
for himself whatever has a bearing on the English watch, without
difficulty. It will be well, however, to supplement it by the special
directions contained in the four following articles:
=478.= =Case, Glass, Dial, Cap, Dome.= In addition to the points
specified in articles =451-452=, the following require attention. See
that the position of dial is not altered by closing down the bezel,
that the fuzee dust cap does not touch the dome or cap, and that
the diamond end-stone or other jeweling of the balance-cock is free
of the case. In ¾-plate watches the chain is occasionally found to
rub against the edge of the case, or the top-plate to press against
the bottom edge of the same, causing the train to bind. See that the
balance and chain and the fuzee great wheel are free of the cap, where
one exists; the chain is especially liable to rub after the breaking
of a strong spring, which may cause the barrel to bulge, when it may
also rub against the potence. Ascertain that none of the dial-plate
feet or pins touch the train, that the hour wheel is clear of the third
and fourth wheel bar, and the minute wheel out of contact with the
dial-plate and not pressed by the dial. See that the third wheel is
free in its hollow, and that the balance, more especially in oversprung
watches, is clear of the barrel.
=479.= =Movement.= The regulator or index must be tested, especially
in watches that are undersprung, at several points between “fast” and
“slow,” to see that it nowhere approaches too near to the spring, is
held with sufficient firmness, and that it never comes near enough to
the guard pin for contact to occur. See that the potence screw and
steady-pins do not project, and that the barrel does not touch the
name-plate, balance-cock, top-plate hollowing or great wheel.
Before taking off the top-plate, notice the position of the detent
in the steel wheel, and the amount of its end-shake; the wear of the
holes, and freedom of the train wheels; the position of the third
pinion with respect to the center wheel, and that of the escape wheel
to the lever; see that the banking pins are not loose or bent; that the
guard pin, which protects the balance staff when the chain breaks, is
near enough to the barrel and the potence. When the watch is taken to
pieces, any loose pillars or joints must be secured, pivots examined
to see whether worn or bent, and those working on end-stones that
they come through the holes. The fourth wheel pinion must be free in
the hollow of the pillar plate and the center wheel in its hollow;
a similar examination also must be made of the collet and pin which
secure the great wheel to the fusee. If a chain is broken near the
barrel end, the stopwork is probably defective or the spring too strong.
The following faults may be met with in the English stopwork. The stop
may come opposite the fusee snail too soon or too late, allowing one
turn too few or too many of the fusee; or the back of the snail may
butt against the stop, and thus stop the watch after going for a few
hours. Overwinding sometimes occurs in consequence of the stop-spring
being locked between the shoulder of the stop and its brass stud; and
the blade of the snail or the end of the stop may be worn or bent in
cleaning.
In ¾-plate fusee watches, see that the balance does not come too
near to the fusee, fourth wheel, center wheel, and sometimes the
escape-wheel. It is to be observed that the breaking of a mainspring
sometimes causes certain teeth of the great wheel to be strained.
=480.= =Escapement.= It may be well to note the few following
particulars that should always be attended to. See that ruby-pin and
pallet stones are firmly set, that neither pallets nor roller is
loose on its staff, and that the lever and pallets are rigidly fixed
together. The guard pin must be firm, the balance well riveted to its
collet, the spring collet sufficiently tight and the curb pins firm. If
there is a compensation balance, ascertain that each screws tight. The
precautions to be observed in regard to the balance-spring are given in
article =456=.
=481.= =Keyless Work.= So great a variety of arrangements of the
mechanism for winding watches at the pendant is met with at the present
day that it would be impossible to give detailed directions in regard
to their examination; the following general remarks, however, mainly
taken from the work of M. A. Philippe on Keyless Watches,[6] will be
found of value in directing attention to the points which most require
it, and will suffice for any intelligent workman. Is should be observed
at the outset, however, that the adjustment of keyless work is almost
entirely a question of depths, and the workman who has thoroughly
mastered this subject will rarely experience any difficulty in dealing
with keyless mechanism.
Carefully observe each depth, etc., in succession, to make sure that no
prejudicial friction occurs either between teeth or by contiguous parts
coming in contact. All springs should act solely in the direction in
which pressure is required of them. Special attention should be given
to the intermediate steel wheel for communicating motion to the cannon
pinion, when this exists, as it is permanently in gear with the train,
so that any unevenness of the depth will effect the rate: if the minute
wheel have too much end-shake or play on its stud, it is apt to ride
on the intermediate steel wheel. The friction of the cannon pinion on
the set-hands arbor must not be excessive, since it would involve too
great a strain on the teeth of the minute wheel, nor too slight, since
the hands would be liable to be displaced on releasing the set-hands
stud. If the intermediate wheel has too much end-shake, limit this by
an eccentric screw overlapping its edge.
Test the spring of the set-hands stud, to see that it is not too strong
nor too weak and that it moves parallel with the plate. Failure in this
latter particular might lead to its rising on to the rocking-bar or
other pieces on which its acts.
The winding pinion depth must be examined to see that it is neither too
deep nor shallow.
The set-hands stud-spring must be strong enough to resist any
accidental pressure on the stud, but, on the other hand, the strength
must not be excessive, as the spring will then be all the more liable
to break, besides causing inconvenience when setting the hands. The
course of the spring should be banked at the point which gives a good
depth between the winding and intermediate wheels. The minute-wheel
stud must be firm in the plate, as any accidental binding might
otherwise unscrew it, occasioning the breakage of the dial. When the
minute hand is carried by the set-hands arbor, and not by the cannon
pinion, care is necessary in fitting this latter, for if too loose
it will rotate in setting the hands without carrying the minute hand
round, and the minute and hour hand will cease to agree.
It is important that attention be paid to the application of oil to
keyless work, as, in its absence, rust rapidly forms, and the mechanism
becomes bound. Of course, all bearing surfaces, such as the interior
of the pendant, intermediate and minute wheel studs, studs or screws
of the rocking bar or other surfaces on which wheels rotate, must be
lubricated; an equally important point is to liberally oil the teeth of
the winding pinion and the bevel or crown wheel that engages with it.
The application of a little oil inside and outside the cannon pinion
must not be forgotten.
TO RAPIDLY TIME A WATCH OR CLOCK.
=482.= It seems desirable to supplement the information here given by a
few details, since we have observed that, either from want of patience
or method, many watchmakers are not always successful in counting the
vibrations.
=483.= =To Practice Counting Vibrations.= At the outset it is to be
observed that to each vibration to the right there is a corresponding
one to the left, so that it is only necessary to observe those in one
direction, or else to count one for each two impacts of the escapement,
in a minute (or half-minute), in order to ascertain the number of
vibrations.
14,400 vibrations per hour correspond to 4 per second; that is 240 per
minute, or 120 per half-minute, and the half of this number is 60.
Similarly, a 16,200 train would give 4½ vibrations per second; or 270
in a minute, the half of which number is 135.
An 18,000 train giving 5 vibrations per second, or 150 per half-minute,
would count 75 in this interval of time.
This being understood, the required number of vibrations is to be
ascertained as follows:
The movement is placed in such a position that the light is reflected
from an arm of the balance, so that, by reference to some fixed point,
(such as the side of the balance-cock, the stud, etc.), each return
of the balance can be noted and counted. A very little practice will
remove any difficulty that may be experienced in doing this. When the
requisite skill has been acquired, one can listen to the impacts of the
escapement while continuing to count, and in order to determine with
greater facility the correspondence of the position of the balance
with successive pairs of vibrations, close the eyes from time to time
while still counting. On opening them, the accuracy of the coincidence
can be at once tested by the sight, and, with a little patience, it is
possible to count the double vibrations with certainty in this manner,
both by the eye and ear; it is only necessary when nearing the end of
the minute or half-minute to continue counting aloud, while keeping the
eye on the regulator: for the ear will guide the voice, which will thus
accurately reflect the motions of the watch.
The above explanations will be sufficient to enable any watchmaker
of average intelligence to acquire the power of counting vibrations,
either in the manner here recommended, or by modifying it in any manner
that may suit his temperament. This power, when once acquired, will be
of very great assistance in his daily work, for before taking a watch
to pieces that requires repair, he can in one or two minutes ascertain
the number of vibrations it should make; he will thus be enabled to
regulate the watch almost instantaneously when the necessary repairs
have been completed. We would again observe that the main point is to
educate the ear to ignore each alternate vibration, and thus to count
only the intervals of the balance being in the same position and the
same phase of its motion.
=484.= =Vibration Counter.= Leclerre’s Vibration Counter is shown in
Fig. 227. R is a ratchet wheel with 30 teeth, mounted on a vertical
plate, so that it can rotate freely. A pawl, _v_, prevents its movement
except when forced forward one tooth at a time by depressing the spring
gathering-click, _p_, a finger being applied to the button, _o_, each
time the word “ten” is uttered. The number of teeth advanced thus
affords a record of the vibrations without there being any necessity to
go into higher figures.
[Illustration: _Fig. 227._]
=485.= =To Regulate a Watch.= Place the movement near to a regulator or
watch indicating seconds, in such a position that the eye can easily
observe the periodical return of an arm of the balance, as already
explained, and commence to count, always starting from the instant at
which the seconds hand points to zero. Then count steadily 1, 2, 3, 4,
etc., until this hand reaches 30 seconds.
Assume, as is very commonly the case, that the balance should make
18,000 vibrations in an hour, or 150 in a half-minute, and that, on
counting its vibrations, we find 65 double vibrations, or 130 beats,
whereas it should give 150. It is thus 20 beats slow. Advance the
index, and repeat the operation; and so on till the regulation is
effected.
A greater degree of accuracy will be secured by counting for a longer
period, say one, two, or three minutes; but when this is done, it is
advisable, in order to avoid confusion, to recommence at one after each
30 or 50 have been counted, because all that is required is the final
deviation.
_Remarks._ 1. All men are not equally quick of perception, so that, in
counting and uttering the word _one_, it will be found to correspond
with the end of the first beat in the case of some observers, and its
commencement with others. By practicing on a well regulated watch, a
watchmaker can determine to which of these classes he belongs. If to
the second, he should double the _one_ at starting; in other words, he
should count thus:
1, 1, 2, 3, 4, 5, etc.
2. Advantage may be taken of the principle of the sounding-board by
placing the watch on a sonorous body which will make the vibrations
louder, or by placing between the plate of the watch and the ear a rod
that is a good conductor of sound. By either or both of these means,
the operation is rendered very easy, especially if the vibration
counter recording the tens is employed.
=486.= =Another Method of Regulating a Watch.= When the movement is in
going order, arrest the balance and make a mark with rouge on one arm
of the escape-wheel. Release the balance when the seconds hand of the
regulator crosses 60. Observing the number of revolutions that should
be made by the escape-wheel in a given time (it would be six turns per
minute with an ordinary 18,000 train), count its revolutions while the
fourth wheel makes one complete turn; indeed, even this counting may
be avoided by making a rouge mark on its edge where it corresponds
with the mark already made on the escape-wheel. If after two or three
minutes these two marks are found to occupy similar positions at the
instant the seconds hand of the regulator crosses 60, the watch is to
time. If there is any difference it is easy to ascertain whether this
indicates a gain or a loss, and the index is moved accordingly.
=487.= =To Regulate a Clock.= The timing of timepieces by counting
vibrations is much more easy than that of watches.
Before removing the pendulum count the number of its vibrations during
two or three minutes. This time will be sufficient to afford a guide in
regulating the clock after it has been repaired.
In most modern timepieces the escape wheel makes 120 revolutions in an
hour, or two in a minute. Hence we have two modes of timing.
(1). Having made a light mark on the circumference of this wheel
opposite to a fixed point, observe if the coincidence is maintained
after intervals of two or three.
(2). Multiply the number of the escape-wheel teeth by 2, and the
product by 120. This gives the number of oscillations the pendulum
should make in an hour. Thence deduce the number it should make in two
minutes, or the number per minutes can be obtained by multiplying the
first product by 2, and it only remains to count the number actually
performed in any definite interval.
=488.= =Guilmet’s Synchrometer.= When a clock is to time, its pendulum
makes a certain definite number of oscillations per minute, dependent
on the train. If, therefore, before taking it to pieces a comparison
pendulum be set to make the same number of oscillations as that of
the clock, or if the former be set to make the number which the train
shows that the clock pendulum should perform, it can be used as a term
of comparison for setting the clock to time after it has been cleaned.
This is the principle on which the synchrometer is based. A pendulum
is lightly supported on a frame, and has an adjustable rod sliding in
a tube, and graduated so that it can be firmly set without difficulty
to give the various periods of oscillation commonly met with in
timepieces. The pendulum is hung freely without any train to drive it,
and continues to oscillate for two or three minutes, quite long enough
to ascertain whether agreement is maintained between the two pendulums.
=489.= =Other Methods of Regulating a Clock.= Various plans have been
recently proposed for rapidly timing a clock, all based upon one
idea: namely, the temporary addition of a seconds hand for purposes
of observation. That suggested by M. Jacomin is recommended by its
simplicity.
Having removed the pin and washer that maintain the minute hand in
position in an ordinary timepiece, replace them by a light brass cap
that can be fixed by a screw or in any convenient manner, so that a
fine steel pin projecting from it shall be accurately in the axis of
the minute wheel. Part of a watch movement, comprising only the center,
third and fourth wheels with seconds hand attached, is supported in
front of the clock dial, so that this pin can be inserted in place of
the set-hands arbor, and it is evident that, if the clock is to time,
the seconds hand should perform one revolution per minute as it will
form part of the clock train. The length of pendulum must then be
varied until this condition is found to be satisfied.
TIMING IN POSITIONS.
HORIZONTAL AND VERTICAL.
=490.= To adjust a watch so that it has the same rate when first placed
in a horizontal and then in a vertical position is a delicate and often
difficult operation; thus it is seldom found to be properly done in
ordinary watches.
The rates in a vertical and horizontal position are made identical
or nearly so by equalizing the resistances that interfere with the
motion of the balance in the two cases, and by taking advantage of the
displacement of the center of gravity of the balance spring.
Satisfactory results will be obtained in most cases by employing
the following methods, either separately, or two or more together,
according to the results of experiments or the rates, the experience
and the judgment of the workman:
1. Flatten slightly the ends of the balance pivots so as to increase
their radii of friction; when the watch is lying flat the friction will
thus become greater.
2. Let the thickness of the jewel-holes be no more than is absolutely
necessary. It is sometimes thought sufficient to chamfer the jewel hole
so as to reduce the surface on which friction occurs; but this does not
quite meet the case, since an appreciable column of oil is maintained
against the pivot.
3. Reduce the diameters of the pivots, of course changing the
jewel-holes. The resistance due to friction, when the watch is
vertical, increases rapidly with any increase in the diameters of
pivots.
4. Let the balance spring be accurately centered, or it must usually
be so placed that the lateral pull tends to lift the balance when the
watch is hanging vertical. In this and the next succeeding case it
would sometimes be advantageous to be able to change the point at which
it is fixed; but this is seldom possible.
5. Replace the balance spring by one that is longer or shorter but of
the same strength; this is with a view to increase or diminish the
lateral pressure in accordance with the explanation given in the last
paragraph.
6. Set the escapement so that the strongest impulse corresponds with
the greatest resistance of the balance.
7. Replace the balance. A balance that is much too heavy renders the
timing for position impossible.
8. Lastly, when these methods are inapplicable or insufficient, there
only remains the very common practice of setting the balance “out of
poise.”
If there is a gain in the vertical hanging position of the watch,
slightly reduce the _lower_ side of the balance; the oscillation will
increase somewhat in extent, and there will be a losing rate in this
position.
The converse must be done in the opposite case.
When the vibration exceeds a whole turn, the changes will be the
reverse of those above indicated. This fact must not be forgotten,
especially in regard to the duplex and lever escapements, which may
at first make a vibration of more than a turn, and subsequently less,
according to the state of the oil.
We would again observe that the timing of a watch for position presents
some difficulty, and it will only be after making a number of trials
that the watchmaker will be able to accomplish it with certainty.
NOTE ON THE PROPORTIONS OF BALANCES.
=491.= Two very important elements in the timing are the weight and
dimensions of the balance; it is, then, necessary that a watchmaker
should practice himself in observing their relative values, and the
effect of increasing one at the expense of the other on timing, and
more especially on timing for positions.
The _sensibility_ of a balance to variations in the motive force, and
the time that elapses between the initial short vibration and the
first that is of normal extent, a time that is approximately constant
will serve as criteria. A balance that is very sensitive to variations
in the motive force is generally too small; and one that attains to
the normal arc of vibration almost instantaneously is, as a rule, too
light. The converse effects would indicate that the size and weight
were excessive.
In order that he may be able to practically apply these remarks, the
workman should gain experience by making observations on several
watches whose rate is known to be good, in the following manner.
In regard to _weight_: Stop the balance at the position of rest of its
spring, then release it and count the number of vibrations up to the
point at which the normal arc is attained; the extent of this must have
been previously recorded on the plate with rouge marks.
Record the number thus obtained in a table opposite to the dimensions
of the balance, and, by comparing these dimensions with those of
another balance of equal size, the weight can be ascertained and also
recorded.
In regard to _size_: Pass through the center pinion a kind of short
screw arbor carrying a large thin ferrule, on which a cord supporting a
weight is coiled. Fixing the movement in a movement holder, set it in a
vertical plane and observe the extent of the vibrations of the balance
with different weights attached to the cord.
These arcs should also be recorded in the table opposite to the
dimensions of the balance. With sufficient practice the watchmaker will
be enabled to judge at a glance whether the weight and size are well
proportioned.
DEMAGNETIZING.
=492.= The following method of removing the magnetism from a watch
that has been accidentally brought under the influence of a powerful
magnet is proposed by Professor A. L. Mayer. We shall not here enter
more fully into the subject than is necessary to indicate the manner in
which a watchmaker may restore the steel work to its original condition.
Take a delicately suspended magnetic needle, say a mariner’s compass,
the length of which is about equal to the diameter of the watch, and
lay it on a table. Now place the watch to be operated on, which should
not be going, on the table close to the needle and on either the east
or west side of it, having previously turned the box around until the
needle points to zero. Taking care not to vary the distance between the
centers of the watch and compass, observe the number of graduations to
which the north end of the needle is deflected with each figure on the
dial brought in succession nearest to the compass; it is also necessary
to note whether the deflection is towards the east or west.
For example, assume that the watch is on the east side, and that, with
noon nearest to the compass, the north end of the needle is turned 12°
to the east, that is, towards the watch. This shows that some point in
the watch in the neighborhood of the number XII on the dial possesses
what is known as “north polarity,” and if the deflection had been to
the west the polarity would have been “south.”
=493.= To take an example. Let the results of a series of trials with
the several hours in succession towards the compass be as given in the
following table:
==========================================================
Hour nearest to the } | I | II | III | IV | V | VI
Compass } | | | | | |
------------------------+----+-----+-----+-----+-----+----
Angle of Deflection | 5° | 18° | 72° | 56° | 22° | 5°
------------------------+----+-----+-----+-----+-----+----
Direction of Deflection | E | W | W | W | W | E
------------------------+----+-----+-----+-----+-----+----
Hence Polarity is | N | S | S | S | S | N
==========================================================
============================================================
Hour nearest to the } | VII | VIII | IX | X | XI | XII
Compass } | | | | | |
------------------------+-----+------+-----+-----+-----+----
Angle of Deflection | 17° | 16° | 16° | 20° | 24° | 20°
------------------------+-----+------+-----+-----+-----+----
Direction of Deflection | E | E | E | E | E | E
------------------------+-----+------+-----+-----+-----+----
Hence Polarity is | N | N | N | N | N | N
============================================================
[Illustration: _Fig. 228._]
It will be seen that the greatest deflection westward corresponds to
three o’clock, and, in the easterly direction, to eleven o’clock. This
shows that the strongest south and north polarity are respectively in
these directions. The first thing to be done is, then, to eliminate
this particular magnetism. Placing a bar magnet in a horizontal
direction, approach the watch to its south-seeking end in such a manner
that a line X X′, Fig. 228, through the axis of the magnet, will pass
through the center C of the watch, the figure XI, which marks the
point of extreme north polarity, being nearest to the bar magnet. Now
cause the watch to oscillate so that it alternately takes up the two
positions A and B, and, when this has been several times repeated,
bring III in a similar manner near the north-seeking pole of the bar
magnet, oscillating the watch in the same way. Again try the watch with
the compass, repeating the above operations if necessary until the
readings are somewhat as follows:
========================================================
Hour nearest to the } | I | II | III | IV | V | VI |
Compass } | | | | | | |
------------------------+----+----+-----+----+----+----+
Angle of Deflection | 5° | 4° | 0° | 5° | 8° | 2° |
------------------------+----+----+-----+----+----+----+
Direction of Deflection | E | E | | W | W | W |
------------------------+----+----+-----+----+----+----+
Hence Polarity is | N | N | | S | S | S |
========================================================
=========================================================
Hour nearest to the } | VII | VIII | IX | X | XI | XII
Compass } | | | | | |
------------------------+-----+------+----+----+----+----
Angle of Deflection | 4° | 4° | 2° | 1° | 0° | 2°
------------------------+-----+------+----+----+----+----
Direction of Deflection | E | E | E | E | | E
------------------------+-----+------+----+----+----+----
Hence Polarity is | N | N | N | N | | N
=========================================================
These figures show that, in counteracting the polarity at III and XI,
the magnetic action of the watch in all other positions has, as might
indeed have been anticipated, materially diminished. Such a condition
of things will, of course, not be attained at once, and it may even
happen that the polarity at the two points III and XI is reversed; in
such a case it is only necessary to oscillate the III in front of the
south-seeking pole instead of the north.
The last table shows that a maximum south polarity is now at V, and
north at I. These points must therefore be operated upon in the same
manner, and, by proceeding in this manner, and successively eliminating
the worst points, the magnetism may be effectually removed.
As proving the efficiency of the above method, Prof. Mayer mentions a
case in which a watch lost one hour in six in consequence of magnetism,
and yet after the above treatment, it resumed its original rate of
about a second per day.
=494.= =Another Method.= A second method of procedure has recently been
described by H. S. Maxim. He employs a specially arranged apparatus,
based on the principle that if a watch or other object be subjected to
rapid alterations of magnetism, while gradually withdrawing it from the
influence of the magnetic poles, the distance ultimately becomes so
great that the reversals are inappreciable, when the watch is found to
be demagnetized. A bar magnet is arranged to revolve in a horizontal
plane around a vertical axis; the watch being placed in a small pocket
opposite to the magnet, is caused to rotate in an ever-shifting
vertical plane, while the frame supporting it rotates in a horizontal
plane. While these movements continue the watch carrier is gradually
moved away from the magnet by the action of a long horizontal screw,
and it is stated that watches that have been completely spoiled can be
rendered perfectly free from magnetism by such an apparatus.
FOOTNOTES:
[6] _Les Montres sans Clefs_ (Geneva).
PART VI.
PRACTICAL RECIPES.
=495.= The practical operations of the watchmaker are numerous and of
a very varied character. Detailed instructions in regard to the proper
conduct of a large number of them will be given in this part of the
work, and frequent references will be made to former parts of this
volume, whenever by so doing repetition can be avoided.
The operations herein discussed are often of so dissimilar a nature
that it has been found impossible to classify them in such a manner
that will always ensure the reader finding the information he requires
without waste of time; and any risk of this would seriously impair
the value of such a hand-book as the present. A very full index has
therefore been added, and when seeking for details concerning any
particular operation, this should in all cases be first consulted.
THE PLATE.
=496.= =To Make a Plate.= The sheet of brass having been prepared in
the manner explained in article =103=, roughly rounded and smoothed on
one face, is cemented to the chuck of a lathe. Turn out the other face
of the plate very flat, and make the circumference square.
When using a lathe the face must first be roughed out, and then the
plate is to be cemented to a perforated plate, so that it can be
centered and finished. Smooth the exposed face with a well-set cutter
and turn the inside and outside of the edge; then make sure that the
whole is concentric by a light cut with a cylindrical drill in the
center hole. After removing and cleaning the plate it is set up in the
dogs, and the face that has hitherto been untouched is gently dressed
with the graver.
There will thus be left a narrow ring at the edge that is not touched
by the graver: this may be levelled with a smooth-cut file, and the
whole surface then smoothed as explained in article =171=.
[Illustration: _Fig. 229._]
If a lathe is not available, the plate must be cemented to an arbor of
the form shown at Y, Fig. 229. The heel of this is received in a runner
of the turns, while the point of the opposite runner is received by the
hole in the center of the plate, which is thereby held in close contact
with the plate of Y, the revolution being, of course, produced by a
bow. While the cement is still hot, a stick resting on the T-rest will
serve to ensure the concentricity of the plate until it is set. This
setting may be rendered more rapid by the application of cold water.
Turn out the plate with a hooked graver made of a worn out file,
and, if the upper or under side does not run true, turn the portion
that projects beyond the chuck with a graver, and, when the plate is
removed, face the surface, taking the flat ring produced by the graver
as a guide, and taking care to avoid altering any portion of it.
The smaller sinks can also be made in the same primitive manner, to
which we have only drawn attention for the sake of watchmakers who are
ill-provided with tools. But we would at the same time point out that,
at the present day, there should not be a single one who does not know
how to extemporize a lathe-head.
=497.= =Cocks and Bars.= If it is required to make all the cocks and
bars of a watch, prepare a _false plate_, the thickness of which is a
trifle greater than that of the highest cock or bar; then turn on the
under side a series of sinks to correspond with the thin portions of
the cocks and bars. Cut the several parts out of this plate with a fine
saw, and it only remains to shape their contours with a file.
The same method may be adopted if a number of identical cocks have to
be made at a time.
THE BARREL.
INCLUDING ARBOR, STOPWORK, MAINSPRING, ETC.
=498.= =To Make a Barrel.= Having trued both faces of the brass, and
drilled a central hole rather less than that finally required and
exactly perpendicular to the faces, turn away the brass from the inside
(leaving a considerable excess of metal at the center to form the
shoulder), and form the ring on which the teeth are to be cut, if it
is a going-barrel, in the ordinary lathe on a wax chuck. Then fasten
the plane surface, which must be quite true, to a smooth plate that
is of uniform thickness and has a hole in the center to permit the
passage of the pump-center. Having fixed the plate by the mandrel dogs,
finish with well-set gravers: 1 the inside; 2 the external cylindrical
surface both of the barrel and of the ring left for the teeth; 3
the barrel-cover groove; and 4 with a fine-pointed cutter slightly
enlarge the central hole. By this means it is possible to ensure that
the barrel will turn true and in the flat. Smooth the inside, more
especially the groove, the corner of which must always be carefully
smoothed and polished.
The cutting of the recess in the barrel-cover (of a Swiss or French
watch) that gives freedom to the motion work, as well as the recesses
for the stopwork, will not present any difficulty when the workman is
provided with a lathe with or without a slide-rest.
[Illustration: _Fig. 230._]
When there is no slide-rest, the tool shown at D, Fig. 230, can be used
for making the groove. A strip of metal of rectangular section has a
small cutter clamped in a slot in its surface at a slight inclination.
By releasing the two screws of the clamp, this cutter can be advanced
to any required extent, and in the strip of metal are two or three
slots having different degrees of inclination, so that the one can be
selected that corresponds with the depth of the groove.
=499.= =To Make the Star-Wheel Sink.= This is easy on the lathe, the
requisite degree of eccentricity being given to the barrel-cover by
means of the pump-center.
=500.= =The Cover: Form of the Groove.= As in making the barrel, a
thick ring must be left at the middle of the cover to be afterwards
removed.
[Illustration: _Fig. 231._]
Fig. 231 is an enlarged figure to show the mode in which a cover
is held in its groove. The two are so formed that the cover shall
pass into the recess with the least possible resistance, and yet be
held firmly without a risk of rotation. It is, nevertheless, a good
precaution to fix a pin in the rim so that it shall prevent such an
accident.
=501.= =Barrel Hook.= It is necessary to observe that a certain amount
of caution must be exercised in regard to the barrel hook, for at
least three-quarters of those met with are badly made. A large hook,
projecting far into the barrel, as often occurs, occupies a needless
amount of space, and at times occasions the breaking of the spring.
One that is badly formed or does not project sufficiently allows the
spring to escape. A hook should project rather beyond the thickness of
the spring; if too thick the spring will be weakened at its eye; if too
thin, it is liable to give when the pull of the mainspring is exerted
on it.
The circumference of the barrel must be drilled through exactly midway
between the bottom and the groove, in a direction that is slightly
inclined, so as to resist the pull of the mainspring. A thread is cut
in this hole with a conical tap, arresting its advance just before
the full threads are reached, in order to make sure that the brass
screw to be subsequently inserted shall hold firmly. Then tap the
brass wire from which a hook is to be made. Allowing a length to
project beyond the screw-plate equal to about one and a half times the
thickness of the mainspring, file the two sides flat, round off the
point, inclining it slightly backwards, and form the hook with a fine
screw-head slitting or other suitable file; then remove the wire from
the screw-plate and hold it in a pin vise.
[Illustration: _Fig. 232._]
The angle _a_ (C′, Fig. 232) is now filed down so as not to project
within the barrel; any burr that might interfere with its introduction
is also removed and the hook is then screwed into its place. It will
be easy to ascertain whether the various heights, etc., are correct
before screwing it tight home. Then screw the hook into position so
that it requires the application of some force in doing so and cut off
the external portion level with the surface of the barrel, employing a
sharp cutting file. But if it appears necessary to withdraw the hook
to make any alteration, this should be done before bringing it to the
final position.
Some watchmakers do not take such precautions; they fit a piece of hard
brass wire to the hole, beveling off the end that is to form the hook,
then cut off the wire nearly flush with the outer surface of the drum
and, resting the back of the hook against a piece of steel, give a blow
with the hammer so as to bend the point of the hook. But this method,
although expeditious, is not the best and it does not always succeed.
=502.= =To Repair a Barrel.= When the play or the end shake of the
pivots is considerable, bush the holes with bushings turned on a smooth
taper arbor. They must not be riveted roughly, as there is a danger
of distorting the bushing or of causing the bottom of the barrel to
“cockle.”
If there is any fear that the bushing will be thus distorted or that
the barrel will not run true after the operation, it will be well to
employ large bushings in which the hole is less than that ultimately
required. Then center from the circumference and enlarge the hole, at
the same time truing it.
Some practical watchmakers, if the bottom of the barrel is thin, or if
special solidity is requisite, fear that the bushing may become loose;
they, therefore, enlarge the barrel-hole and make it square; then bush
it with a piece of plain brass, and having centered the barrel by its
circumference in the lathe, drill a central hole.
It is hardly necessary to observe that, when the holes in both barrel
and cover require to be operated upon, a pin should be fixed so as to
prevent the latter from rotating in its groove; so that before finally
removing the barrel from the lathe, the cover can be put in position to
have its center accurately adjusted with a long pointed graver.
=503.= =A Barrel That Does Not Run True.= The remedy for this has just
been indicated: enlarge the holes and rivet in them bushings that are
either plain or have only very small holes. The two holes can then be
accurately centered with a slide-rest and cutter of the requisite form.
[Illustration: _Fig. 233._]
It is a very simple process, and yet there are some workmen who, either
from not possessing a lathe or ignorance as to how it should be used,
set the barrel on a screw arbor, and, after having topped the teeth,
round by hand those teeth which have been touched. This method of
procedure is longer than the former and gives results that are worse;
moreover, since the screw-arbors are rarely themselves true, especially
in regard to the cones, which will be found to have a play on the axis,
it is far better to set the barrel in cement on an arbor of the form C,
Fig. 233, on the center pin of which the barrel-hole fits without play;
the middle of plate C must not be too thickly coated with cement.
=504.= =Barrel Out of Upright.= Several methods may be resorted to for
adjusting a barrel that does not turn flat on its axis. Assume that the
holes are not too large, for it has just been shown that by bushing
the holes and truing them on the lathe, it is always possible to ensure
that a barrel shall be true on its axis.
To true it without renewing the holes, first try turning the cover
round in its groove by successive short stages, and test its truth each
time; the arbor being clamped in a pair of sliding tongs and a card
held close to the teeth. If, after the entire circumference has been
tested, no point is found that satisfies the requisite conditions, the
edge of the cover must be gently hammered (a piece of silver paper
being first laid on the anvil so as to avoid marking the gilding) on
the side at which the teeth pass farthest from the card and the effect
of the operation must be tested. This hammering should be done very
carefully and little at a time, and if too great a strain is put on the
cover to force it into the groove, some metal must be removed from the
side opposite to that at which the hammering occurred. Hence, if the
one side is too much extended in the first instance, so that a large
amount of metal has to be removed from the opposite side, the operation
is liable to be unnecessarily long and difficult. It is hardly
necessary to observe that we are here referring to the modern form of
going-barrel, in which the cover is on the opposite side to the teeth;
in the older form, where the reverse is the case, the opposite edge of
the cover must be hammered.
Sometimes a barrel that runs true on its arbor is found to incline when
mounted on the plate: such a fault is due either to the barrel holes
being too large or to the sink that receives the ratchet not being
parallel to the plate. This sink must be trued in the lathe while in
position, screwed to the plate of the watch.
[Illustration: _Fig. 234._]
=505.= =To Adjust a Post or Curb in Position.= Make a small punch, a
front and side elevation of which are shown at _p p_, Fig. 234; harden
it and let it down to a yellow temper at the point. Now fix a flattened
ball of lead in the vise, the upper surface of which is so formed that
the portion of the barrel that is to receive the hole for the post may
rest securely. There is no necessity for the entire barrel to rest on
the lead. Place a small piece of mainspring, _q_, within the barrel
against the circumference, where it will be maintained by the punch
_p_, which will also hold the barrel steady on the lead block. Then
give a moderate blow with a heavy hammer on the head of the punch,
forcing its point through the barrel.
A burr will be produced outside the barrel, while there will be a
corresponding depression within, especially in front of the hole. To
secure clean edges, pass a file over the external projection, but only
sufficiently to remove its crest, and, resting the inside of the barrel
on a lead block, drive inwards the metal that projects; then pass the
punch through in a direction opposite to the first and of course with
less force. Remove the burrs and repeat the operation first on one side
and then on the other with gentle blows of the hammer, removing the
punch by hand. Finish with a very fine file, which will entirely remove
any external burr round the hole, and one cut with a slide-rest cutter
in the inside, followed by charcoal and oil.
A watchmaker that has never performed this operation will do well to
experiment with the punch on a small plate of brass, or, still better,
on a worn-out barrel.
To insert the post, coil up the mainspring in the winder so as to be
able to introduce a slightly conical piece of steel or brass between
the two last turns of the spring and near to the hole. Place the post
in position and hold it and the spring while the wedge that keeps the
coils apart is removed. If the opening thus secured was found to be
insufficient, it might be increased by introducing a screwdriver, which
is held down until the post is inserted. The making of this curb, shown
at _b_, Fig. 234, will offer no difficulty.
[Illustration: _Fig. 235._]
=506.= =Stopwork.= If the pitch circles of the finger-piece and
star-wheel of several Geneva stops be measured, it will be seen that
three different proportions may exist (Fig. 235), in which the former
is less than, equal to, and greater than the latter respectively.
When the finger-piece has a greater diameter, as at _d_, it will oppose
an increased resistance to the hand in winding, but the direction of
its pressure against the stop will be much below the center of rotation
of the star-wheel, because the finger is necessarily very short.
When the finger-piece is very small, as at _a_, there will be less
resistance opposed owing to any want of freedom of the star-wheel,
and the pressure against the stop will be more nearly tangential, the
finger being relatively long; but more care will be required in the
construction and, for a given force applied to the key in winding,
there will be a proportionately increased pressure against the
star-wheel axis.
Inconveniences thus increase in proportion as either piece is enlarged
as compared with the other, and the best proportion is secured by
making the two diameters equal, as shown at _c b_.
The stud on which the star-wheel rotates should be cut square or,
preferably, slightly conical downwards.
=507.= =To True a Star-Wheel.= The form of a star-wheel can be adjusted
on the lathe, on the tool shown in Fig. 208, using a cylindrical
mill-cutter and adding a stop so that the branches of the tool are
always brought to the same distance apart.
Star-wheels can be bought of the material dealers, but they are not
always equally divided; indeed, some exist that have been merely
punched in the punching press. Hence it follows that many of them are
characterized by at least one of the following faults: teeth of unequal
length, or with their concavities of unequal form.
[Illustration: _Fig. 236._]
When the teeth are well formed and finished at their ends, but of
unequal length, this arises from the star-wheel having been badly
centered during the operation of cutting; it must then be re-centered.
Take a small brass plate H, Fig. 236, and drill a hole at its center,
with a notch at the edge, _a_, to receive the convex tooth without
shake. Now place the plate in the lathe and turn out a sink to receive
the star-wheel and hold it firmly. The convex tooth will then drop into
the notch and the wheel should project a little above the face of the
plate. Now release one dog, and, having gripped with it one tooth of
the wheel, take a fine-pointed graver and true the central hole and the
sink that receives the screw head, taking care only to remove a small
quantity of metal at a time.
If the workman has not considerable experience in using the lathe and
fears a derangement in releasing and again tightening the dog, he had
better remove the plate, cement the star-wheel in position and replace
it, when it can be re-centered with the pump-center.
=508.= =To Make a Finger-Piece.= After having drifted the square hole
in the center of a steel disc of suitable dimensions, and traced
out a line to mark the circumference of the disc and the end of the
finger, drill two holes a little beyond this line, leaving such a space
between them as to ensure that the base of the finger shall possess
sufficient strength; but these holes should be drilled so far in
towards the center of the disc that freedom is left for the corners of
the star-wheel teeth during its rotation. The head of the finger is at
first left so as to exactly fit the spaces of the wheel without play,
this being subsequently given with a fine file and in the smoothing.
File the circumference all round so as just not to touch the line
traced out; then, putting the disc on an arbor, hold a fine _barrette_
file against the edge, and cause the arbor to oscillate backwards
and forwards, the file coming in contact alternately with each side
of the finger. This smoothing of the rim will materially facilitate
and abridge the final work with the graver. The corner of the rim on
one side of the finger having been finished off with the graver edge,
reverse the arbor between its centers to treat the other corner in a
similar manner. A finger-piece made as here explained will be found to
be very true.
Some watchmakers, when it is possible, finish the circumference after
it has been adjusted on the barrel-arbor itself; but as a rule this is
not necessary.
The slit that receives the pin may be cut as follows: File a square
piece of brass to fit the hole in the finger-piece, cut a notch across
the end with a screw-head file, and insert it in the square hole.
Having centered a flat cutter, the thickness of which is equal to that
of the slit to be cut, on a taper arbor, place this in the lathe;
resting the brass horizontally on the T-rest (which had better be at
the back of the lathe, so that the progress of the operation may be
more easily observed) and present the notch to the cutter.
=509.= It will be understood that the foregoing details relate to the
method to be adopted in making the finger-piece by hand, but it is very
easy to arrange an addition to the ordinary lathe, with or without a
throw, for rounding or truing the circumference with great rapidity.
Having mounted a circular mill-cutter on an arbor in a chuck, as seen
at R, Fig. 233, replace the =T=-rest by an upright that has a shoulder,
and is truly cylindrical, and of a diameter to fit the support without
shake; the finger-piece, D, is fixed to its upper end by a cone and
nut, as in the screw-arbor, or by any other means. A lever _l_ is
adapted to the vertical rod, so that it can be rotated between two
stops on the lathe-bed; such stops are, however, not always needed,
because by employing a thick cutter that is smooth on the face there is
no danger of damage to the finger. At the same time, if there are no
stops, considerable care is requisite in the smoothing and polishing to
prevent the sides of the lap touching the finger. This can be polished
afterwards in a very short time by using a lap that has been turned
on the edge to fit the notch. It is useless to enter into further
particulars, as the little appliance or one of an analogous description
can be easily made.
The apparatus shown in Fig. 195, and described in article =402=, could be
employed for such a purpose.
=510.= =To Make a Clock Barrel.= A strip of soft brass, thicker than
the circumference of the drum is intended to be, is coiled into a
circle rather less in diameter than the required barrel, on a cylinder
of hard wood, either by pressure between the jaws of a vise, or with
a mallet or hammer. The two edges, after being carefully cleaned, are
soldered with silver solder or brazed, while they are held in position
by a piece of binding wire wound round the drum.
Placing this ring on the nose of a beak-iron, harden it by gentle
blows, so as not only to harden the brass, but also to increase the
diameter and make a true cylinder.
Chuck it on a cylinder of hard wood in order to turn the two ends
square, and form the edge that is received in a groove cut in the
bottom of the barrel; the bottom is then soft soldered in position. In
the older barrels that contained very strong springs, it was often the
practice to leave tongues projecting round the drum that entered holes
in the bottom and were riveted on the other side.
The barrel may be cemented to a large wax chuck that has as its center
a short arbor tapped and provided with a washer and nut, or it may be
gripped by its base in the universal head, and the surfaces, etc.,
finished.
Some of the details given in regard to a watch barrel are applicable
here.
The drum is now no longer made by bending a strip of brass, except in
country towns, because brass tubing is always to be obtained in cities
at metal warehouses, which only needs to be cut into rings of the
requisite length.
=511.= =To Make a Barrel-Arbor.= If the metal is in the rough and has
the scale on, it must be cleaned either on the stone or with acid.
The following method of procedure has been proved in practice to be
expeditious:
When the arbor has been turned to shape with the graver, smoothed, and
almost polished, it is placed in the barrel and should rotate when in
position, but with considerable friction. Then make the two squares as
explained below (=513=); and, after smoothing that which receives the
finger-piece, set this latter in position on the arbor and see that
it does not descend quite to the shoulder. Then replace it by a worn
out finger-piece, or by a copper disc that is cut so as to allow of
the insertion of the pin in exactly the same position as is required
by the finger-piece to be definitively used. It is then easy to drill
the pin-hole from either side of the square and to smooth it with a
fine broach. Each time that the arbor has to be inserted in the barrel,
great care must be taken to remove any burr, as it might damage the
barrel holes.
Before hardening the arbor, cut in it two grooves of moderate depth at
the points at which the ends must be broken off. Such a practice has
two advantages: 1. The two waste points of the arbor can be removed
and each end partly formed without employing a file, an arrangement
whereby it is possible to maintain in the arbor a maximum of hardness,
at least at the winding end. 2. If the arbor is distorted, it will not
be in the body, but from the points at which these cuts are made. If
any distortion occurs, the blow-pipe jet can be directed on the points,
which are then removed with a file before the final polishing.
=512.= To harden the arbor, place it in an iron tube and surround
it with powdered charcoal which is pressed down, having previously
been well dried. When the whole has been heated to the requisite
temperature, throw it into water, and, if the precautions already
explained under hardening are adopted, the arbor will be found to be
smooth and clean and without either scales or blisters on its surface.
Clean and polish it; this latter operation will give the proper freedom
to the pivots, although it often happens that a touch with a broach is
required in the two holes.
[Illustration: _Fig. 237._]
The bevelled groove within the ratchet teeth is polished by rotating
the arbor while a small steel plate, perforated at its center and of
the form shown in plan and section at Z, Fig. 237, is held by the hand
against the groove. The shoulders can be easily and rapidly polished in
the tool represented in Fig. 44.
[Illustration: _Fig. 238._]
=513.= =To Make the Squares. To Make Drifts.= The tool shown in Fig.
238 is used. On the plate P, which is at right angles to the foot S,
is fixed a frame that carries two hard steel rollers, _c_ and _d_, the
edges of which are extended to form a guide.
A bent finger _b_ is hinged on a screw on the side of the plate, and
has a hole _j_ drilled in it, which is continued for a short distance
into the plate P.
The following is the method of using the appliance: Fix to the arbor
a disc, indicated by dotted lines, in the circumference of which are
four equidistant notches to receive the nose of the finger _b_. The rod
S takes the place of the =T=-rest and the arbor is placed between the
centers of the lathe. As S can be raised or lowered to any position
and the runners can be moved laterally, it is easy to bring the point
at which the square should commence to correspond with the line _n
n_. The finger _b_ having been inserted in one of the notches of the
division-plate, reduce the arbor with the file L. Move _b_ to the next
notch, and repeat the operation, and so on with the other two sides.
If there is any danger of the finger not maintaining a sufficiently
firm hold of the plate, a tight-fitting pin can be inserted in the hole
_j_.
At first the arbor should be filed away less than is actually required,
and the only adjustment necessary to ensure this is the raising of S
to a suitable height. No difficulty need be experienced in this, but,
if any doubt is entertained, a screw may be supported from the bed of
the lathe, terminating in a rod that passes through the plate P, as
indicated at _t_ for example, thus securing perfect regularity in the
upward and downward motion of the system.
If a tapered square is required, it will be sufficient to slightly
incline the frame by means of two screws _v i_, placed near its
left-hand edge with their ends resting on the plate P.
=514.= =To Drill Exactly Through the Center of the Arbor.= Of course,
if the old arbor-nut is available, it will afford the best guide
for performing this operation, and, if the arbor is tapped, such a
hole will not be required. But when neither of these conditions is
satisfied, the workman will have two slight difficulties to overcome:
the drilling of the arbor and its nut exactly in the center and
parallel to the plane of the ratchet. By adopting the following method,
he can easily satisfy these conditions:
[Illustration: _Fig. 239._]
=515.= Take a brass disc D, Fig. 239, turned smooth on its two faces.
Enlarge its central hole until the barrel-arbor enters it to such a
distance that a blow of a mallet will drive it up against the ratchet
where it should hold firmly. This disc is chucked on the lathe and a
groove is formed that passes exactly through the center. Ascertain by
means of a douzieme or a thickness gauge whether the thickness of the
disc, measuring from the bottom of the groove to the under side, is
equal to the space between the shoulder of the arbor that corresponds
to the outside edge of the barrel hole, and the point at which the hole
should be drilled. If the thickness is excessive, diminish it from the
under side; if, on the other hand, it is not sufficient, fit some thin
discs on the arbor, and then force the brass disc to the position thus
determined upon. It is hardly necessary to add that when this is done,
holes must be drilled to some depth on either side of the arbor, using
a drill that does not shake about in the groove although quite free and
inclining slightly downwards so that the hole shall not be above the
point determined upon, namely, the bottom of the groove. Continue the
drilling until the two holes meet, the drill being maintained, during
this part of the operation, parallel to the face of the ratchet.
[Illustration: _Fig. 240._]
=516.= If the workman is not provided with a tool for cutting the
groove exactly in the axis of the disc, the accuracy that is so
essential can be ensured as follows: A brass rod G, Fig. 240, is
divided into four at the end as near the center as possible by means of
a fine saw or a file that only cuts with its edge, which will be used
to form the groove. Set the rod G in the lathe, a center of the form
_f_ being inserted at _b_ where the slits cross, and turn down the rod
G _b_, although only a little metal should need to be removed, until
it enters the hole in the brass disc and projects a short distance on
the other side. It then only remains to insert in one of the notches
of G _b_ the cutting file or the saw previously used, to form a groove
on the surface of the disc that passes exactly through its center; it
is to be remembered that the saw, etc., must only cut with its edge,
and should enter the notch with a very slight friction, sufficient to
indicate that it fits without play.
=517.= =The Arbor-Nut.= The usual practice is to make the diameter of
the nut equal to one-third that of the inside of the barrel. With thick
springs of but slight flexibility it must be larger so as to avoid
overstraining the innermost coil, and, conversely, with a very thin
spring it is diminished, rendering the employment of a longer spring
possible. When the nut is too small the spring must be made long, and,
by setting up the stopwork, a coil of the spring can be maintained
always on the nut.
=518.= _To drill the nut along a diameter._ By means of the rod G, Fig.
240, draw a straight line to indicate a diameter of the nut. This line
will serve as a guide for marking two points opposite to one another on
the circumference, round which a circle has previously been traced with
a graver. The points should be marked so deeply as to ensure that the
drill does not displace itself in the initial stages of the drilling;
with a little caution, and using a glass, very little difficulty will
be experienced in ensuring that the points are in a right line. One of
the two following methods may be employed for drilling the nut:
[Illustration: _Fig. 241._]
1. Prepare a brass block of the form shown at _f p f′_, Fig. 241, the
space A being cut away, and the end _p_ provided with large-headed
screws, shown at _v_, _v_, in the plan. The two faces, _f_, _f′_, must
be parallel to each other, and at right angles with the face _p_, a
condition which can be easily satisfied by means of the lathe, the face
_f′_, for example, being turned towards the headstock, and the dogs
introduced into the space A; the opposite face _f_ is then trued with
the slide rest. In the vertical face _a a_ make a round hole, through
which a pointed center passes, being pressed forward by a spiral or
other spring, and the point corresponding exactly with the line _a a_
traced on the face of the brass; of course the axis of this center must
be at right angles to the same line. A small block may be inserted
within the space A to prevent any flexure of the arms.
An inspection of the figure will make clear the manner in which this
little tool is to be used. Having fixed the nut on the face _p_ by the
screws _v v_, so that the two points on its circumference coincide with
the line _a a_, the whole is placed in the drilling tool with the dogs
pressing either on the upper external face or in the space A. After the
block is fixed, ascertain by rotating the uprighting spindle that its
point coincides in all positions with the top mark on the edge of the
nut, and drill as usual. Drill one side, invert the block, and proceed
in a similar manner to drill the other.
The little appliance above described might be simplified by being made
of the form shown at E, which would require to be reversed when the
second hole is about to be drilled.
=519.= =To Polish the Inclined Faces of Ratchet Teeth.= Set the ratchet
in slow rotation by means of the foot-wheel, and bring a strip of
spring covered with coarse rouge and oil against it from the side,
resting the strip on the =T=-rest. In a very short time the teeth will
be rounded and polished. This process is similar to that adopted at the
present day for polishing the inclines of cylinder escape wheels in the
lathe. The position of the polishing spring and its inclination must be
determined upon by trial, so as to make sure that the entire surface of
the tooth is acted on.
[Illustration: _Fig. 242._]
=520.= Another method is to make a small boxwood lap, and arrange it
as shown at M, Fig. 242, so that, when caused to revolve on its axis,
which may be more or less inclined, it is brought into contact with the
ratchet wheel with its axis, as indicated by the figure. The teeth will
cut into the wood, and trace out a helix, as seen at M′, and the lap,
passing successively into the ratchet teeth, will cause it to revolve
rapidly. When the groove is deep enough, apply some coarse polishing
rouge to the surface of the drum; after a few rotations the faces will
be found to be polished.
The arbor and lap may be arranged in either of two ways.
Mount the lap between the centers that carry the cutter in a
wheel-cutting engine and support the barrel-arbor opposite to it in a
vertical direction between the chuck and the bent arm or “gallows” used
to fix a wheel while cutting its teeth.
A watchmaker who is not provided with this tool must chuck the lap in
the lathe, then mount the barrel-arbor in such a carrier as is shown
at _p p_, Fig. 242, and, resting its base on the =T=-rest, hold the
ratchet against the lap, determining the most suitable height and
inclination by trial; this, he will find, can be easily done.
=521.= =To Polish the Circular Groove in the Ratchet.= It takes a
long time to accomplish this by using first, an iron polisher with
oilstone dust, then one of copper with rouge and oil. The operation
can be performed more expeditiously by using an iron runner, as shown
at B, Fig. 243. The end is rounded to correspond with the groove; and
the hole, which is indicated by dotted lines, should be large and
funnel-shaped, so as to avoid contact with the corners of the winding
square when a see-saw motion is given to B in the polishing.
[Illustration: _Fig. 243._]
The arbor being cemented to a chuck in a lathe, hold the end _o_,
charged with oilstone dust or rouge, in the groove, and, while the
arbor revolves, rotate the spindle B in the hand, at the same time
giving it a see-saw motion as above mentioned. A very little practice
will be required to do this.
=522.= =Repairing a Barrel-Arbor.= Cement the arbor _a a_, Fig. 244,
to the lathe chuck, turn down the ratchet, removing its teeth and thus
diminishing its diameter by about a third, as shown at _n n_; then
reduce the thickness to a half, turning it down on the side next to
the winding square, and continue this square down to the flat disc that
remains, taking care that no shoulder is left at the angle between the
two. The arbor is now in a condition to receive the new ratchet which
has to be fitted.
[Illustration: _Fig. 244._]
Adjust a flat ratchet _r r_ like those used on the barrel-arbor of
a fusee watch, which must be of the thickness and diameter of the
original ratchet, so that it exactly fits the winding square; turn a
sink in it, as shown by the dotted line, to receive the disc already
formed; and, if the hole fits the winding square freely but without
play, and this square is carried down to the disc, the dust cap _c c_
will maintain the ratchet in its position as effectually as though it
formed one with the arbor.
By adopting the above method, which does not occupy much time, it is
often possible to avoid making a new arbor when all but the ratchet is
sound; and if this portion should again wear out, the necessary repair
is still further simplified.
We are assured that arbors repaired in the above manner showed no signs
of wear after fifteen years, except that the square in the ratchet was
a trifle enlarged, though not sufficiently to interfere in any way with
the efficiency; moreover, in modern watches, the winding square is
generally long, so that the ratchet can be left somewhat thicker at the
center and a corresponding sink cut in the under side of the dust cap
to receive it.
=523.= =To True a Barrel-Arbor that is Coned Inwards or too Large.=
Cement the arbor firmly to a chuck as shown at C, Fig. 245. With care
it will be easy to make the part _e_ run true. As a rule, but very
little metal requires to be removed to make _e_ cylindrical or conical
in any desired direction, and it will generally be sufficient to finish
by polishing with an iron polisher and oilstone dust or coarse rouge
and oil. Use a narrow polisher that only bears on the end of _e_,
giving it a double movement, straight forward and in a half circle
towards one side; or else use a broader polisher, supporting it on the
=T=-rest. By inclining this, the iron can be prevented from touching
_e_, except near its extremity. It is unnecessary to add that when
the arbor has been made cylindrical or coned in a given direction a
suitable polisher, bearing on the entire length of _e_, can be used.
[Illustration: _Fig. 245._]
Either of the two following methods can be adopted in the place of that
above explained: Support the winding square end of the barrel-arbor in
an eccentric runner; let the opposite end run in a small coned hole
in the end of a steel runner, which must be polished and hardened so
as to prevent the corners of the square that receives the stop-finger
from wearing it away; now apply coarse rouge until the fault no longer
exists and follow with fine rouge to complete the polishing.
If not provided with an eccentric runner, it will be sufficient to take
a tight-fitting key, drive it on with a blow of a hammer and file a
point at the tapped end so as to be in the axis of the barrel-arbor.
Having attached a ferrule to this key, place the whole between the
runners and proceed as explained above.
=524.= =To Renew a Worn Winding Square.= The best plan is to make an
entirely new arbor; but when this cannot be done, as, for example,
on the ground of expense, the following method of repair may be
attempted: Direct the blow-pipe flame on to the square while holding
the body of the arbor in a pair of pliers, so as to prevent its
being over-heated; and round off the corners of the square, leaving
the diameter no greater than is necessary for strength, and tap it
with a screw-plate. Now drill a hole at the end of a piece of round
steel of somewhat greater diameter than the original square, and form
an internal screw by means of a tap made in the same hole of the
screw-plate as was used for the arbor; the end of the tap should be
tapered and with good cutting edges.
If the arbor is the full length allowed by the case, reduce the length
slightly and screw on the small steel spindle, tapped to the right
depth. It must not be screwed quite down to the ratchet, although
intended ultimately to come into actual contact. After having thus
tested it, form the square, which will naturally be rather larger than
the original, and cut a deep groove with the graver at the point where
the square is to be broken off, but, before breaking it, harden and let
down to a blue or violet temper; then smooth, polish, and screw finally
on to the arbor. If this last operation does not result in the square
breaking away, grip the spindle in a vise, and, taking the square in a
pair of long-nosed pliers, break it with a sharp blow. It only remains
to finish off the end in a screw-head tool.
THE MAINSPRING.
=525.= A free and uniform action of the mainspring is one of
the primary conditions that have to be satisfied for ensuring a
continuously good rate.
=526.= _To make the eye in a Mainspring._ Every watchmaker knows that
this is commonly done by means of a mainspring punch; but in its
absence a hole can be made by hammering a pointed punch one or more
times through the end of the spring after it has been softened, and,
after filing away the projecting metal, the hole is broached out or
enlarged with the point of a graver and finished with a rat-tail file,
taking care that the corners are rounded off so as to avoid the risk of
cracks.
=527.= _To reduce the height of a Mainspring._ This and the following
method are only to be resorted to when a new spring cannot be obtained.
Introduce the spring into a barrel of less height than itself and wear
the steel away by rubbing it on a hard surface charged with oilstone
dust, keeping it constantly rotated between the fingers. When the
reduction is sufficient remove the spring and draw-file it, so as to
round off the two edges; then clean the entire surface.
=528.= _Selecting a Mainspring: Adapting it to a Fusee._ The spring
that is characterized by the most uniform uncoiling and the least
difference between the force exerted when fully and only partially
wound up will generally secure the most constant rate. In selecting one
for a going-barrel watch, or in adapting to a fusee, the adjusting rod,
shown in Fig. 246, and described in article =530=, is used.
THE FUSEE.
=529.= At the outset, we would state the three characteristic
properties of a fusee that have led to its adoption and retention in
high-class watches and marine chronometers: 1, it equalizes the motive
force; 2, it enables us to use a _tapered_ mainspring, in which the
uncoiling takes place in the most advantageous manner possible; and, 3,
it secures a longer period of going.
[Illustration: _Fig. 246._]
=530.= =To Adjust a Fusee to Its Mainspring.= Set the barrel and fusee
in position in the frame, with the mainspring and chain carefully
hooked in their places, and the former set up about half a turn, and
grip the fusee square in the clamp, _d n_, of the adjusting rod, shown
in Fig. 246; then wind up the mainspring by rotating this lever with
the hand until arrested by the stopwork. Now slide the weight _m_,
which is held by friction and a light spring, along the rod until a
point is reached at which the lever just neutralizes the force of the
mainspring, so that the whole rests in equilibrium when left to itself.
Rotate the rod backwards by half turns at a time. If equilibrium is
maintained to the end, the fusee is well adjusted. But when this is not
the case, it will be found that the weight of the lever is too great
or too small; showing that the radius of the fusee is either too small
or too great. Adjust the lever so that it balances with the radius of
the fusee, which is thus shown to be most deficient, and at all other
points along the thread of the fusee more metal must be removed to an
extent indicated by the experiment.
When not provided with a fusee engine, it is a common practice to use
the ordinary lathe, and an equaling file smoothed on its two faces; or
a templet might be adapted to the =T=-rest of such lathe.
If the irregularity observed is but slight, it is advisable not to
touch the fusee; because, in the great majority of cases, an equipoise
can be arrived at by altering the degree to which the spring is set up.
Thus, if the weight is too heavy for the lower coils of the spring, set
it up more, so as to increase its tension; in the converse case, of
course, it must be let down. By trying several springs, especially if
they are of different manufacture, it will very often be found possible
to secure a sufficient degree of uniformity without there being any
occasion to re-cut the fusee.
CHAIN.
=531.= =To Ease a Chain.= When the links are rusty or not sufficiently
supple, the chain should be placed in oil and left there for some hours
at least. Round off the edge of a boxwood block, cut a groove across
this edge, and clamp the block in a vise; then place the chain like a
saddle in the groove, so that it hangs down on either side. Applying
oil liberally to the wood, take an end of the chain in each hand, and
pull it backwards and forwards in the groove, renewing the supply of
oil at intervals. When perfectly flexible, the chain must be cleaned
with benzine, or, after soaping, wash it in water and leave for some
minutes in alcohol. After being dried, it is dipped in fine oil and
dried in a clean linen rag free from fluff, pressing the rag against
the edge. A chain treated in this manner will be found to remain supple
for a long time, and it will not be liable to rust.
=532.= =Riveting a Hook, Etc.= When riveting either a hook or link to a
chain, it is very necessary that the end of the rivet be cut or filed
quite square; for, otherwise, the blow of the hammer will bend the
rivet, so that the chain will not be square on the barrel, neither will
the riveting be firm.
WHEELS.
=533.= =To Rough Out a Wheel.= The sheet brass having been prepared
in the manner indicated in article =103=, one face is smoothed with a
file, followed by oilstone dust; the plate is then set up in the lathe,
to true the other face with the slide rest. On the smoothed face trace
out the rim and the crossings. These latter can best be marked out on
the dividing plate, or _grammaire_, already explained in article =343=.
[Illustration: _Fig. 247._]
After drilling the small holes, _a_, _c_, etc., Fig. 247, at the
corners, cement the wheel to a plate that is perforated to permit the
use of the pump center, and remove the metal between the crossings by
first turning the sinks indicated by the shaded disc _s_ with the slide
rest, and subsequently cut the groove _i i_. Now center the wheel in
the lathe, and trace the arcs _a c_ with a fine graver, moving the
face-plate backwards and forwards in the manner referred to in article
=364=.
Remove the wheel from the plate, and finish off the spaces with a
file. Two files will be needed for forming the angles; one a flat
barrette file, with the corner beveled off and smoothed to nearly a
right angle, to go against the rim of the wheel; and the other a taper
file, with faces of the same curvature as the inside of the rim, its
two edges being inclined at rather more than a right angle and smoothed
carefully. If these simple precautions are not taken, there is a risk
of cutting through the arms or making them too narrow.
Many of the details in the following article, although specially
relating to a balance, will be found applicable to the construction of
other wheels.
=534.= =To Make a Plain Balance.= The round plate of which the balance
is to be made must be hammered with the greatest possible care, and
of a thickness but little greater than that of the finished balance
(=103=). Smooth one face and cement it either to a perforated plate
through which the pump center can reach the balance (if the universal
head is to be used), or on the chuck of an ordinary lathe, or on
the wax chuck C, Fig. 233. Hollow the middle portion with the slide
rest cutter or hook tool, according to the kind of lathe used; but,
whichever it be, it must be very well set, and only remove a small
portion at a time. The application of an excessive pressure will
produce a kind of rolling action, which will induce a tendency in
the arms to bend. Remove the metal between the rim and boss until
its thickness is diminished by about a third; smooth this surface
carefully, finishing with a piece of charcoal. The disc is now ready
for crossing out.
Place it on the dividing plate (see article =343=) to mark out the
three arms, and remove the metal between them, either in the lathe, as
explained above, or by drilling a series of holes parallel to the arms
and rim. These holes should be so arranged that they can be enlarged
with a fine-pointed graver (while the balance rests on a flat wooden
block or is cemented to it), and a turn with a sharp edged broach, or
the passage of a thin rat-tail file should be sufficient to separate
the useless metal. As a rule, the series of holes is drilled with the
disc held against a wooden block, but the burrs produced on the under
side by the drill prevent it from being maintained flat, unless they
are removed after each hole is drilled, and this might occasion a
distortion of the disc. It would, perhaps, be better to cement the
rough balance to a sheet of zinc; the color of the shavings would
suffice to indicate whether the hole was through.
The arms and rim must be made smooth and even with nicely formed
crossing files, the edges of which are smoothed to the most convenient
angle, as already indicated.
In filing the crossings the balance should rest against a small block
in the vise, and they are rounded while resting in a groove at the edge
of a similar block, specially shaped for the purpose. This block is
also useful as a support in finishing the angles between crossings and
rim.
The under face of the balance is smoothed with oilstone dust; and the
arms by drawing the polisher along them while the balance rests on a
flat block; it is then cleaned and fitted on a very true arbor, as
A, Fig. 233. This should pass through the center hole of the balance
without play after a broach has slightly enlarged it, and the balance
is clamped by a cap and three screws, _j_. It only remains to set the
arbor in the lathe and polish the rim, first turning it to a half
oval if desired. In the latter case the rim, after being smoothed, is
polished first with coarse rouge on hard pith, and subsequently with
fine rouge on softer pith.
=535.= If the arms of a balance are found to be too long, so that
they curve, the rim must be lengthened by hammering with the greatest
possible care; the inside and outside of it must then be trued on an
arbor of the form A.
The boss at the center will be found thicker than is desirable; its
height can be reduced with the balance merely adjusted on a smooth
taper arbor, but it is necessary to observe that the balance and
arbor must not be adjusted to each other by pressing or by rotating
the balance with the rim held in the fingers. It must be pushed on or
off the arbor by applying pressure at the center of the boss on one
side or the other with a piece of hard wood resting firmly against the
=T=-rest, while you cause the arbor to rotate.
Instead of the form of arbor shown at A, a screw arbor might be used,
with its cone pressing against a cap, but the balance must always be
carefully adjusted on the arbor, and this latter must run perfectly
true.
=536.= =To Make a Number of Identical Wheels.= If it is desired to
make a number of brass wheels of the same size and shape, the workman
will find it much to his advantage to employ the punching machine.
By adopting the following method he can make his own punches and
bed-plates.
[Illustration: _Fig. 248._]
With a view to secure same length in the matrices that are used
for forming the crossings, without augmenting the difficulty of
construction, proceed thus: Each of the pieces V, V, Fig. 248, consists
of two parts: 1. The star-piece, _a c b d_, of three, four, five or
six arms, according to the number of crossings of the wheel. 2. The
collar, V. The star-piece is of the same length as the collar, and is
made in the wheel-cutting engine in the same manner as the leaves of
a pinion. The punches, of which one is shown at P, are fitted by hand
to the recesses of the star-piece, and then cemented in position; the
whole is then chucked in the lathe and turned as one piece, so that
its diameter is slightly greater than the interior of the collar. Now
harden the star-piece, and temper it to a blue color. When cold harden
the collar V _v_, and temper it to the same degree, but, while expanded
by the heat in tempering, introduce the cold star-piece and drive it
home. By proceeding in this manner, no subsequent hand fitting will be
required. V _n_ must not be hardened.
Tools for punching the crossings of wheels are sometimes made on this
system in which the disc of brass is fixed to a support that can be
made to revolve by quarters of a revolution at a time, and a single
punch serves to remove the metal by four separate operations. But as a
rule it is better to use four punches together.
=537.= =To Repair Wheels.= When the teeth of a wheel are damaged, the
only possible remedy is to provide a new one. If, however, a single
tooth is broken, the following method can be adopted, on an emergency,
for inserting a new one:
[Illustration: _Fig. 249._]
=538.= _To insert a new tooth in a wheel._ Cut a small notch in the
rim of the wheel, shown at _a_, Fig. 249, which should be dovetailed
if possible, and the two sides spread out slightly from the upper
towards the under side, as indicated at _c c_. Cut a small piece of
well-hammered brass, of the form B, so that the part _d d_ fits exactly
into the notch in the rim. Now invert the wheel and grip it near to
_a_ in a pair of long-nosed pliers, which must be held in the vise.
Moisten the inner faces of the notch with soldering fluid and, placing
B in position, put particles of solder round its edge; holding the
lamp beneath the nose of the pliers, the solder will presently melt,
and a drop of the fluid should be added to facilitate its running into
the joint. Cool the wheel and wash thoroughly, first with water and
subsequently with alcohol.
It only remains to file both faces smooth and level with the rim of the
wheel; then shape the tooth carefully.
By introducing B from the side opposite to that which is visible in
the watch, and sloping the faces _d d_, to a less degree than _a_, the
inverted wheel will present a recess to receive the solder; so that, on
looking at the upper surface, at which the edges fit very closely, the
joint will be scarcely visible.
=539.= _To true a wheel._ When the teeth are found to be in good
condition, but the wheel does not run true, or one or more of its
arms are strained, the fault can be corrected, in a case of absolute
necessity, as follows:
Remove the pinion from its wheel. Enlarge the central hole in the lathe
and rivet or solder in it a brass ring that is slightly thicker than
the wheel, and perforated with a smaller hole than that required for
the riveting. Now center the wheel from its circumference; increase the
central hole with the slide-rest cutter, and turn down the two faces
of the ring level with the wheel. Rivet the pinion in its place, after
testing the truth of its riveting neck, when the wheel should be found
to turn both true and flat.
If the wheel under repair is likely to be subjected to much force, at
least two small notches should be left in the enlarged hole in the
wheel to receive corresponding projections in the brass ring.
=540.= If the _crossings of a wheel are broken_ and the wheel cannot
be replaced, it must be chucked in the lathe and the arms turned out
with a graver, the inner edge of the rim being at the same time turned
circular, and a step turned on this edge where the metal is to be left
of half its original thickness.
Take another wheel of the same size and thickness, or a plain disc, and
turn it of the same diameter as the outer ridge of the step; reduce its
thickness at the edge by one-half and a disc will thus be obtained with
a ridge round the edge corresponding exactly with that of the wheel,
and the one will fit in the other. They are, of course, soldered in
this position, care being taken to prevent the solder from reaching the
teeth, and the old wheel will thus be provided with a new interior.
If the disc is made to fit closely on the upper side, a wedge-shaped
ring being left to receive the solder in the manner explained in
article =537=, the joint will be scarcely perceptible on the exposed
face, even with a glass.
In repairing delicate wheels in any way it is a good precaution to
cement the rim to the edge of a hole in a brass plate, so that only the
arms or other part to be operated upon is exposed.
=541.= =To Make a Stem-Wind Wheel.= We will suppose that the old wheel
is available as a pattern; if it is not, the several dimensions must be
ascertained by calculation in accordance with the laws of depths.
[Illustration: _Fig. 250._]
Prepare a thick plate, and drill a central hole, fitting a steel pin
into it as shown at _o d_, Fig. 250. The diameter of _d_ must be
exactly the same as that of the pump-center in the universal head. Fit
the wheel-blank R to the pin _o_ without play, and cement it to the
plate. Remove the pump-center and insert _d_ in its place, clamping
the plate P firmly against the face-plate by the dogs. By using
well-sharpened gravers or cutters, the wheel may be rapidly shaped.
The pin might be forced in from the under side to the level of that
face of the plate; and if it were perforated as shown by the dotted
lines, it might be centered by means of the pump. Or the plate P might
be made circular and centered from its circumference.
=542.= To cut the teeth on the circumference the wheel need only be
fixed on the chuck of the wheel-cutting engine as usual by means of the
steel cone. The crown teeth are cut while the wheel is firmly cemented
to a pin-chuck like that used in turning it.
Other keyless wheels can be made on the same principle, and such
modifications as may be necessary experience will suggest. Sufficient
information in regard to wheel-cutting has already been given in =397=
and following articles.
PINIONS.
=543.= =To Make a Pinion.= At the present day pinions of all sizes can
be obtained of the material dealers, so that it is very seldom that a
watchmaker is obliged to make one for himself.
In an emergency, however, he can adopt the following method for making
one out of the ordinary drawn steel; but it should be added that, in
all probability, some practice will be needed before success is arrived
at. Cut a length of steel wire of suitable diameter about two-thirds as
long as the files that are to be used for shaping the teeth. Turn it
down to form the axis, leaving a block near each end equal in length to
the required pinion, as if three pinions were to be made on the same
staff. Then cut and round leaves on all, keeping the file always in
contact with a leaf of each pinion. By proceeding thus the sides and
roundings of the leaves will be maintained parallel to the axis, and
there will be no risk of the pinion being barrel-shaped, as is nearly
always the case when a short pinion is held in the fingers or rested on
a block in the vise.
Proceed in the same manner in smoothing and polishing, using pieces of
some close-grained wood, such as walnut.
It is much easier to make the pinion of the required form by means of
a revolving cutter in the lathe, if the workman is not provided with a
special tool for the purpose: the arrangement of the lathe is described
in article =402=.
In some factories the leaves are cut in two operations: a cutter with
plain fine saw teeth divides the circumference into the requisite
number of equal parts, the leaves being subsequently made of the
correct shape by a special cutter, the method of making which has
already been very fully explained in articles =417-435=.
=544.= =To Determine the Size of a Pinion.= The following table is
usually employed for this purpose. See also =562= and the following
articles.
To give the approximate diameter of a pinion, the pinion caliper should
include:
For 16 leaves, 6 full teeth; that is to say, measuring the distance
between the two external faces;
” 15 ” rather less than 6 teeth, or 5 teeth, and just beyond
the point of the sixth;
” 14 ” 6 teeth, measuring at the points.
” 12 ” 5 teeth, measuring at the points (or rather 4½ teeth);
for a clock-wheel, 5 full teeth;
” 10 ” 4 full teeth;
for a clock-wheel, 4 _squared_ teeth;
For 9 leaves rather less than 4 full teeth, or 3 full teeth to the
point of the fourth;
” 8 ” 4 teeth, measured at the points, minus a quarter of a
space;
” 7 ” rather less than 3 full teeth;
for a clock-wheel, 3 full teeth, plus a quarter of
a space;
” 6 ” 3 teeth, measured at the points, or rather more;
for a clock-wheel, 3 full teeth.
It is important to notice that these measures can only be regarded as
a first approximation, and it is only by actual trial in a depth-tool
that we can be certain that a pinion is correctly sized. By taking the
measures in a micrometer, or other accurately divided gauge provided
with a vernier, the work of selecting will be much abridged; but how
long will it be before the generality of watchmakers will make use of
these convenient appliances? The well-known wheel and pinion sector,
although convenient, is not equal to them in point of accuracy, and is
affected by an error in measuring a chord, not a true diameter of the
wheel or pinion.
=545.= =To Increase or Decrease a Pinion.= The pitch circle of a pinion
may be increased by reducing the thickness of the leaves in such a
manner that their flat faces are continued further on to the rounding;
conversely, a pinion may be decreased by carrying this rounding farther
down towards the base of the leaf.
=546.= =To Decrease a Pinion Without Removing the Wheel.= Some
watchmakers recommend that the wheel be removed from the pinion,
and, after the necessary reduction has been effected and the leaves
re-polished, again riveted on the pinion-neck. Very few workmen,
however, can do this well, so that after the operation the wheel is
seldom found to run true. If a new pinion cannot be procured, the old
one must be reduced.
When a pinion that is too large is replaced by one that is smaller, it
is necessary to take care that the hole in the wheel is well centered
and not too large; in either of these cases it must be enlarged and
bushed after being centered by the circumference.
=547.= =To Polish Pinion Leaves Mechanically.= It was formerly the
custom to polish the leaves of a pinion, holding it on a block or
between two fingers and traversing a strip of metal with oilstone dust
backwards and forwards in each space for the smoothing, and a similar
strip of walnut wood (with rouge) for polishing.
This method has long been abandoned in factories, where all pinions are
polished in a machine.
We will proceed to explain a simple arrangement for polishing pinions
in the ordinary lathe, but it is advisable first to describe one form
of tool that is actually in use on the large scale for this purpose.
The two only differ in their dimensions.
=548.= _Pinion-polishing Machine._ A frame B B, Fig. 251, supports
at its upper end an =H=-shaped piece, of the same form as the
cutter-holder in an ordinary wheel-cutting engine; but the arbor,
instead of carrying a cutter, is provided with a wooden drum R. On the
base of the frame is a plate P, which can be fixed by the screw E,
and carries a second plate _p_ to serve as a bed for the slide, which
supports the pinion to be polished freely between two brackets _a_,
_a_. The plate _p_ can be set a little oblique and clamped by the screw
_v_.
[Illustration: _Fig. 251._]
The machine acts as follows: Present a corner of a pinion-leaf to the
circumference of R (which is caused to revolve by a cord passing round
the pulley _n n_), the axis of the pinion being not quite at right
angles with that of the drum, in order that the groove formed in the
soft wood may resemble the thread of a screw, and so cause the pinion
to revolve. When the groove is of sufficient depth, apply rouge if
operating on a small pinion, and emery for a large one: after a few
turns of R, the slide carrying the pinion being at the same time moved
backwards and forwards, the pinion will be found to be polished. A
better surface can be obtained by using flour emery.
The steel wheels of keyless work can be polished in the same manner.
=549.= The spindle of the screw E passes through a rectangular slot in
B in order that the slide and its support can be moved parallel to the
axis of R.
The grain of the wood must be at right angles to the axis of rotation
of the drum, and a wood that is non-fibrous is preferable. It must
evidently not be too hard, and, if too soft, the thread formed on its
circumference will get rough, and often will suddenly change position.
When the entire surface has been worn it must be re-turned smooth and
cylindrical. The larger a roller is, the quicker it will polish and
the less it will wear. Moreover, it will render a proportionately less
amount of motion of the slide necessary. The root of the walnut tree is
especially sought after, but, when this cannot be obtained, other woods
can be used.
In factories where clock pinions are made, thin discs are employed
in place of the drums. They are at least a decimetre (4 inches) in
diameter, and very narrow at the edge, and can be re-turned with a
graver when worn without being removed from the tool, if a =T=-rest be
fixed in some convenient position.
The screw _d_ is for limiting the descent of the drum, but some workmen
prefer to dispense with it, and, instead, hold the frame C C in the
hand, pressing it gently against the pinion. They urge that the wood
is never of the same degree of hardness round its circumference, and
therefore must of necessity wear irregularly; by holding C C in the
hand the pressure on the pinion can be more evenly adjusted, as it is
possible to feel at once whether the drum is polishing or scratching.
The inclination of the slide to a plane at right angles to the axis
of R is measured by the pitch of the screw formed on the drum. But in
practice no special precautions are taken, and it is only necessary to
incline the slide slightly to the right or left, until the pinion is
found to revolve freely.
The drum may be from two to three inches in diameter, and, in order to
ensure the same degree of hardness throughout the entire circumference,
it is a good plan to make the drum of a series of wedges cut so that
the grain in all radiates from the center. Beautiful polished surfaces
are obtained in this manner.
[Illustration: _Fig. 252._]
=550.= _To polish a pinion in the ordinary lathe._ Various methods may
be adopted, but the following is one of the commonest:
Support the pinion between the two centers _b_, _d_, of the
pinion-carrier shown in Fig. 252, the form of which will be evident
without explanation. Rest this carrier by the portion M against the
=T=-rest, pressing it against the drum at the same time with one
finger. Rotating the drum first by hand, make the pinion cut a groove
varying the inclination until it is found to be correct, and, when
sufficiently deep, charge with polishing material, and rotate it with
wheel, at the same time moving the pinion-carrier backwards and
forwards endwise. A little experience will give the requisite skill.
If the pinion is not held at a sufficient inclination it will scrape
and will not revolve. If too much inclined, only the roundings of the
leaves will be polished, the sides being left untouched. A well-formed
groove will last for a long time.
=551.= =To Tighten a Cannon Pinion.= If it is simply slack it will be
sufficient to increase the diameter of the set-hands arbor as described
in article =336=. But if the cannon pinion is in the habit of working off
this arbor when setting the hands, the arbor can be tapered a little
downwards; or proceed as follows:
[Illustration: _Fig. 253._]
Drill a hole in the square that receives the minute hand in the
position shown at _a_, Fig. 253, and also indicated by dotted lines at
_c s_; now turn a groove round the arbor, also shown by dotted lines,
at the point _n_, to correspond with the hole _a_. Insert a pin in this
hole, filing it off smooth with the surface at the side at which it
enters, and nearly level at the other side, to be hammered over just
sufficiently to prevent the pin from working its way out. The cannon
pinion will now be found to turn with the requisite degree of friction,
and without any tendency to work up. It will last all the longer if
both the pin and the groove in which it works are polished.
SET-HANDS SQUARE.
=552.= =To Make a Set-Hands Nut.= This is a small square nut pinned to
the pivot of a solid cannon pinion that projects beyond the top-plate
in some watches after passing through a hollow center pinion. This
construction has been latterly discontinued, but it may be well to
explain the mode in which such a nut can be renewed when necessary.
[Illustration: _Fig. 254._]
Take a rod of soft steel of a diameter half as large again as that
of the square to be made. Drill a hole along its axis rather less in
diameter than the set-hands arbor and cut off the ends a little longer
than the square is required to be. Put this nut on an arbor and turn it
flat on each end (although still a little long) and truly cylindrical.
Having inserted a loose fitting coned brass wire of oval section into
the nut, hold it on its side on an anvil. With a sharp blow of the
hammer cause the cylinder to assume an oval form, so that the round
hole is as seen at A, Fig. 254, this being the section of the end of
the set-hands arbor itself. If the work has been carefully performed up
to this point, the steel nut should now pass a short distance on to the
arbor on applying a moderate pressure, and it will suffice to slightly
alter the form of this latter in order to ensure a perfect fit. As
there should be no shake, it is advisable that this adjustment be made
after the nut is hardened.
File the two faces _d_ and _f_ parallel to each other and to the axis
of the oval, reducing the total thickness very nearly to the amount
ultimately required, then holding the nut in the pincers by these two
faces firmly, but without scratching them (or it may be held by a rod
fitted to the oval hole), form the square, removing all the metal that
is beyond the two vertical lines in the figure. Then set it on an oval
arbor and turn the corners down to the exact diameter required; pass
the graver over the two ends so as to adjust the length. It will then
be easy to finish off the square and round the lower end, holding
the nut on a steel rod in a pin-vise. Drill the hole for a pin after
marking its two ends on the nut as explained in article =518=, then,
holding the nut so that it rests on its lower face, form a recess with
a chamfering tool held in its axis; the form of this can be modified if
required with the rounded end of a rod and oilstone dust.
Harden the square and temper it to a blue color; then smooth its faces
and ends, and fit the square to the set-hands arbor. The hole for the
pin must now be made through this arbor, taking care not to allow the
square to rise out of its place during the operation. It only remains
to polish the recess formed in the nut with a rod rounded at one end
and rotated with a ferrule, and finish off the corners with a burnisher
and rouge; the lower end is finished in the same manner as the head of
a screw.
=553.= We have here considered the case of a new arbor, but, if fitting
a nut to one that is already drilled, proceed as follows: Make the nut
rather longer than necessary and drill a hole higher than the point
at which measurement shows it ought to be; then remove metal from the
lower face until the two holes coincide. The work is simplified if the
nut be made of the correct height at once and, instead of drilling a
hole, a slit be formed as in the head of a screw, the bottom of which
must correspond with the lower edge of the hole in the arbor.
=554.= =To fit the Set-hands Arbor to the Center or cannon pinion.=
We have pointed out in article =364=, the objections to hammering the
set-hands arbor so as to secure sufficient friction to make it hold
in either of the pinions through which it passes in the ordinary form
of watch. Tracing a spiral line on its surface is not much better, as
the metal thus caused to project soon wears off. A better method is
explained in article =337=, but, when only a slight increase of diameter
is needed, the following will suffice:
Roll the arbor on a hard flat wood surface with a file of medium cut,
applying considerable pressure so that the arbor is forced against the
file. If the pressure is sufficient and maintained long enough, a dead
rough surface will be formed on it which will increase its diameter so
that it will retain a small quantity of oil. It is well to roughen the
surface rather more than necessary, subsequently passing a burnisher
lightly over it until the arbor fits the pinion with sufficient
friction.
As to the making of a set-hands arbor, it will present no difficulty to
a watchmaker of even average skill in turning and filing.
PIVOTS.
=555.= =The Play Of Pivots.= It may be accepted as an approximate rule
that the play of escapement pivots in their holes should be as follows:
In the cylinder escapement, about one-sixth the diameter of pivot.
In the duplex escapement, about one-tenth the diameter of pivot.
In the lever escapement, about one-eighth the diameter of pivot.
A large hole causes the pitching of the depths to vary with position,
and a deficient play renders the escapement more sensitive to
thickening of the oil.
The depth of a pivot-hole or the length of its cylindrical acting
surface may be taken to vary inversely with its hardness. Thus a ruby
hole is made less deep than one of brass.
=556.= =To Replace the Pivot of a Hollow Pinion.= It often happens that
the pivot of a hollow center pinion is so deeply cut that it cannot
be re-polished, in consequence of the careless manner in which too
many examiners finish the center holes (=461=). If the pinion itself
is found to be still in good condition, it can be made serviceable as
follows:
Cement the pinion, with its wheel attached, firmly to the chuck of
a lathe after having removed the two worn pivots, and, when it is
accurately centered, increase the hole by means of a drill that is a
trifle larger than the original pivots (see article =282=); in the hole
thus enlarged and carefully smoothed insert a close fitting steel tube
that has been hardened and tempered to a blue color, which must be
smoothed and run true. The portion of this tube that projects on either
side is then adjusted to the proper length, and it only remains to
polish the pivots.
If only one pivot requires renewal, ascertain whether there would be
sufficient hold with the hole enlarged through half its length, and
proceed as already explained.
We have assumed that the shoulders of the original pivots can be made
to serve again, but it often happens that the shoulders do not possess
sufficient substance, in consequence of the hollows being cut too
deep. In such a case it is hardly necessary to observe that the hole
must be drilled larger, so that, after the tube has been adjusted, new
shoulders can be turned on it.
=557.= =To Redress a Bent Pivot.= For this purpose some workmen merely
use a pair of pliers or tweezers; others place the pivot in a slot of
the Jacot tool, and press on it with a burnisher that has little or no
cut, at the same time causing the staff to rotate. Either of the two
following methods may be adopted:
Drill a number of straight holes in a plate exactly at right angles to
its surface. Now introduce the pivot into a hole that it fits with very
little play, and redress it by causing the staff to rotate, at the same
time holding the plate in the hand. Caution is necessary since there is
some risk of bending the pivot too far.
=558.= =Pivoting a Cylinder, etc.= This operation will not present
any difficulty if the several heights are properly taken. See also
the articles on Beaupuy files (=240=), and on compasses for measuring
heights, etc. (=243=).
=559.= =Polishing Pivots in the Lathe.= Pivots are as a rule polished
by metal polishers provided with suitable materials, and held in
the hand; in Fig. 255, however, is given the design of a machine by
which this work can be accomplished when the pivoting is done in the
chuck-lathe, the pivot itself being free and unsupported by a runner.
[Illustration: _Fig. 255._]
The bed P of the instrument carries a wheel R which engages with a
pinion on the axis of the polishing lap _m_. The wheel R is mounted on
a clock stud passing through a slot and fixed by a nut, so that the
pitching of the two mobiles may be modified; motion is communicated
to the lap by simply placing the finger against the teeth of R. The
bed can move in a vertical plane, being pivoted on two screws, _v_,
_v_, and the block that receives the points of these is riveted to the
disc _d d_, which can be made to rotate, with friction, on the second
disc _n n_. This latter is riveted to a plate _e_ fixed at the end of a
cylindrical rod F.
It will be evident that if the rod F is inserted in the =T=-rest
support, the plate P extending towards the back of the lathe, this
plate can be raised or lowered, and moved towards the right and left,
so that the flat face of the lap can always be brought in contact with
the pivot that is to be polished. This latter is caused to rotate by a
foot-wheel while one hand holds the raised plate by the button _a_, and
a finger of the other hand is applied to the teeth of R, causing the
lap to rotate.
The upward motion of P may be limited by the edge of the top _s_ of the
button _s k_, which is tapped so as to rotate with stiff friction on
the pillar H. The stop _l_ is to prevent the polisher from traveling
too far towards the left and thus removing too much from the shoulder
that is to be polished. The screw _x_, giving motion to the slide _y_,
is for securing parallelism between the pivot and the surface of the
lap, according as the former is cylindrical or conical in shape.
For fine pivots it is advisable to introduce an additional wheel and
pinion. The finger will then be better able to appreciate the degree of
resistance opposed, and, owing to the increased velocity, it will be
useless to use oilstone dust, but rouge can be applied directly after
the turning. At _e_ is a steady-pin for maintaining the position of the
instrument.
BUSHING PIVOT HOLES, ETC.
=560.= Every watchmaker knows how to proceed in adjusting an ordinary
perforated bushing or stopping. We would make a few remarks on the
subject of bushings generally.
The tapped bushing is very firm, but, in order that it may be well
centered, it is essential that its thread fits exactly the tube of the
tool (=322=), and that the pointed rod is exactly central. A turned
bushing, especially when a broach can be passed into it after it is in
position, is more easily made central (see article =342=).
When bushing holes that are rather large with solid bushings, after
the hole has been marked with the pointer it must be drilled with a
small drill, a larger one being subsequently passed through, so as to
increase it. Otherwise there is great danger of the hole turning to one
side.
If a hole, such as that of the center wheel, is bushed with a
perforated bushing, it will often be found to incline towards the
barrel or fusee, so that the hole is displaced. Such an inconvenience
may be avoided by using a bushing with a hole smaller than is
ultimately required, afterwards enlarging it with the plate centered in
the lathe.
=561.= =Riveting of Bushings.= Some watchmakers have found considerable
advantage in replacing the sudden and irregular impacts of a hammer
by gradual pressure, without shock, obtained by a small press worked
by hand on the principle of a punching machine. With a well made
bushing, the flat end of which is slightly rounded, and the inside
of the hole in the plate finished with a rat-tail rather than with a
cross file, it is found that the riveting is always perfect. Others
employ an ordinary pair of sliding tongs, the noses of which are
drilled to receive two punches, one flat and the other rounded, as in
the mainspring punch. Three pairs of punches suffice for all sizes of
bushings, and the same tool can be used for closing up screw-holes, etc.
[Illustration: _Fig. 256._]
=562.= =Movable Bushings.= These are for use in regulator clocks
and others of large dimensions, and a few words must suffice for
their description. They are the invention of M. Alleaume, and will
be understood from Fig. 256. It is always desirable, with a view to
prevent wear, that when metal pivot-holes are used, the pivot should
bear on a length equal to about three times its diameter; but for such
a condition to be satisfied, it is essential that the axes of both
holes and pivots be absolutely parallel. The figures will at once
show in what manner such parallelism is secured. C C is the plate, in
section, in which a hole is made of the form indicated by the lines
that bound the cross-hatchings. The movable bushing A is held against
a shoulder, and prevented from rotating by a screw, the point of which
enters a small hole in the bushing. The pivot of B passes into A, and
this latter is capable of such slight motion as will insure contact
between the surfaces throughout their length.
DEPTHS.
=563.= =To Secure a Good Depth.= The least skillful of watchmakers
can, without much difficulty, place a wheel in the depthing tool in
conjunction with a pinion, and change this latter until the two are
found to run easily together. But there are comparatively few that are
sufficiently acquainted with the subject of depths to be able to select
a pinion whose proportions are such as to satisfy the greatest number
of the conditions to be fulfilled by a good depth.
This unsatisfactory state of things is due in great measure to the
employment, without any correction, of tables of the sizes of pinions
(=544=), according to which these sizes are determined by a measurement
on the teeth of the wheel, taken with a pinion caliper. This method,
although sufficient for ascertaining the size approximately, and even
for securing a depth that runs more or less easily, cannot be accepted
as an unvarying rule.
Far from resting on any mathematical law, as ignorant men urge in their
attempt to instruct others, it is only true for a particular number and
form of tooth in regard to the wheel, and a definite thickness of leaf
and shape of the rounding in regard to the pinion. It ceases to be true
if applied to other numbers of teeth, or to pinions that have their
leaves thicker or thinner, or the roundings different from those of the
pinion first determined upon.
=564.= _Theoretical and practical depths._ The fundamental principle
of every depth is as follows: To determine what curvature should be
given to the teeth of the wheel which drives, in order that the tooth
that follows (whether its side be straight or formed according to a
pre-determined curve) shall be driven in such a manner as to secure the
best transmission of force, a transmission which is in part influenced
by the uses to be made of the machine.
=565.= Teeth formed like the involute of a circle have very marked
advantages, but they cannot be adopted in practice, especially in the
case of the leaves of pinions. The epicycloid can be realized very
approximately in the teeth of wheels in horology, and such teeth can
be used in conjunction with pinion leaves having straight faces, the
construction of which does not present any difficulty. This explains
why the epicycloidal form has been adopted by watchmakers; but,
although it is more easily drawn than the majority of other curves,
there are still some obstacles in the way of its general application,
mainly dependent on industrial requirements. The difficulty is usually
got over by forming the tooth according to a circular arc, nearly
identical with the epicycloidal curve, see articles (=440-42=).
=566.= When two mobiles are of the _same diameter_, the theoretical
depth will be characterized by having teeth and spaces of equal width;
but, since in practice the friction with such an arrangement would be
excessive, owing to its taking place on both sides of the tooth, the
teeth of the wheel that are driven are so far reduced in thickness as
to secure the necessary freedom.
=567.= When the two mobiles are very highly numbered, the lead is
short, so that the tooth of the wheel may be a trifle broader or
narrower than the space without inconvenience.
But when using pinions of low number (from 6 to 10 leaves), this is not
the case. In proportion as the width of the wheel tooth is reduced,
its ogive becomes shorter, and the most advantageous portion of the
lead (that beyond the line of centers) becomes less. And, besides this,
account must be taken of the slipping towards the end of the lead, and
the reduction in the difference between the geometrical and the total
diameters of the wheel.
=568.= To secure a good depth with low numbered pinions, the leaves
should not be more than half the thickness of the space. If they are
thicker than this, it may be found necessary to reduce the width of
the wheel teeth, when the pitching is insufficient; but the most
serious objection lies in the fact that the pitch circle of the
pinion will be diminished in diameter. Let there be two pinions with
circular roundings and of the same total diameter, but having leaves of
different thicknesses—that with the leaves thick will be found to be
too small, etc.
=569.= =To Calculate the Vibrations of a Pendulum or Balance.= Multiply
together the numbers of teeth of the wheels, starting with the one that
carries the minute hand (which therefore makes one revolution in an
hour), but exclude the escape-wheel.
Multiply together the numbers of leaves of the pinions, commencing with
the one that engages with the center-wheel.
If the first product be divided by the second, the number obtained
gives the _number of revolutions_ of the escape-wheel in an hour.
Multiply this figure by _twice the number_ of teeth of the
escape-wheel, and the product is the _number of single vibrations
performed by the balance or pendulum in one hour_.
ON THE APPLICATION OF THE GEOMETRICAL LAWS OF DEPTHS TO PRACTICE.
=570.= It has been urged that when the geometrical forms of the leaves
and teeth, as given in scientific treatise, are accurately carried
out in practice, the depths are found to be unsatisfactory and liable
to cause occasional stoppage; and these facts are brought forward as
evidence that theory and practice are at variance.
On the contrary, theory and practice are in perfect accord: the
apparent disagreement arises from an error in the application of the
geometrical laws.
In copying the theoretical forms of the teeth of wheels and leaves
of pinions, it would be necessary to ascertain that they were
mathematically exact, and this is impracticable. Two conditions must be
borne in mind:
1. Theory shows that the mobile which drives should be made a trifle
larger than the geometrical size, so as to counteract imperfections in
the workmanship.
2. A pinion is _never_ made of the exact mathematical proportions,
in consequence of the processes that have to be adopted for cutting,
polishing, centering, etc. If a number of pinions be taken, and
if the several dimensions of each be determined by means of a
micrometer measuring to hundredths of a millimeter (or from two to
three-thousandths of an inch), differences that are, comparatively
speaking, large will be found in the diameters, measuring between
corresponding leaves; in the thickness of leaves; in the diameters
of the circles at which the roundings join the straight faces, and
the general truth of the pinion will nearly always leave something to
be desired. It should be added that these faults will be more marked
according as the leaves have been more quickly made.
The teeth of wheels will be found to be characterized by similar
faults, although they are less marked.
=571.= It follows from these facts that, in watches and timepieces, the
_pinion is always a little smaller_ than theory would require; thus the
epicycloid should be struck with a somewhat smaller generating circle,
and the ogive of the tooth will be proportionately reduced.
The _practical conclusion_ at which we arrive, then, is as follows: As
it is impossible to secure absolute perfection in the teeth of small
horological mechanisms, their ogives must be slightly more rounded at
the points than the designs given in scientific treatises indicate,
since these latter are drawn exactly in accordance with the geometrical
laws.
These remarks are of the greatest possible importance to the
manufacturers of both watches and timepieces; they point to the fact
that not only the ogives of all wheel teeth should be lower than theory
indicates, but also that, in commoner work, they must be still lower,
according as the pinions are of more inferior quality.
=572.= =To Alter a Stem Winding Pinion Depth.= The depth of the Stem
Winding Wheel and Pinion often occasions considerable inconvenience,
and its adjustment requires to be accurately made: when the depth is
too deep, its alteration is easy, as the roundings of the pinion leaves
can be reduced, or the stud or other piece that carries the winding
wheel can have its base a little reduced on one side, so as to set the
wheel a trifle out of upright (but so slightly as not to be perceptible
to the eye, and taking care that the teeth remain on a level with those
of the barrel-arbor wheel). A shallow depth is somewhat more difficult
to correct. If a sufficient change cannot be made by altering the
support of the winding wheel, one of the following methods must be
resorted to:
1. Reset the pendant of the case.
2. Make a new winding pinion of greater diameter, increasing the number
of its leaves by one, to correspond to this change.
3. Alter the position of the movement in the case.
The two first methods are more especially applicable to new work, while
the third is more convenient for repairers, although of course it can
only be resorted to with advantage when the pinion has a bearing in
the pendant. The requisite change in the position of the movement can
be produced by raising the rim of the case that supports the plate, or
by soldering two thin strips of metal on this rim, producing a similar
effect; one on either side of the pendant will suffice, except when a
considerable change is necessary, in which case they should be set at
intervals around the rim to avoid an obvious inclination of the dial.
Or four holes can be drilled at equal distances apart around the edge
of the plate and in its plane, so that their edges overlap the position
occupied by the rim of the case; pins are then set in these holes and
filed away until they produce the requisite amount of elevation. Or,
again, flat-headed screws may be fitted around the edge with their axes
at right angles to the plane of the plate and their heads on the dial
side.[7] The depth will then be adjusted by screwing these screws more
or less into the plate.
It is advisable to ascertain that the dial is not forced too near the
glass, as such is occasionally found to be the case, necessitating the
bevelling of the edge of the former.
PALLETS.
=573.= =To Advance a (visible) Jewel in a Pallet.= Workmen that
have had much experience of escapement making do this without any
difficulty by holding the pallet arm in a pair of tweezers that have
been slightly warmed, but ordinary repairers will not succeed with such
a method: they can however, effect the required change as follows.
[Illustration: _Fig. 257._]
Make a small brass plate, E, fig. 257, with a piece _c_ projecting
upwards, which the screw _v_ traverses with stiff friction. A saddle
_b_ is fitted to the edge of the plate by screws. A glance at the
figure will suffice to show the mode of using it; the pallet arm whose
jewel is to be adjusted is clamped under _b_ with the jewel just
opposite the screw _v_. Now turn this screw until it stands at the
distance from the impulse face of _a_ through which the jewel is to be
advanced; taking the plate in a pair of long-nosed pliers, hold them
over a small lamp flame, and press with a small screwdriver lightly
against the point _a_ so as to advance the stone by the requisite
amount as soon as the shellac is sufficiently soft. A particle of
shellac is placed at _a_, if any cavity forms during the process,
and the plate is laid on some cool body, avoiding contact with the
pallet-staff.
If the stone projects below the lower surface of the pallets, a small
washer must be placed underneath before clamping the screws of _b_, of
such a thickness that the stone is just on the level with the surface E.
=574.= =To Alter the Form of a Pallet Face.= Workmen that possess the
requisite skill and steadiness of hand can alter the form of a pallet
jewel, when it is necessary to modify the height or form of the impulse
face, by simply using a copper polisher charged with diamond powder.
The polishing material employed is always decanted in very pure oil, as
otherwise it is apt to scratch instead of polish. The coarser quality
is first used when a material change has to be effected, but if only a
very slight alteration is necessary, and the adjustment has to be very
exact, only the finest quality must be used, as there is a danger of
making scratches that would be very difficult to erase. We would also
add that this operation requires some skill and patience.
[Illustration: _Fig. 258._]
=575.= =To Measure the Lift and all other Angles, etc. of the Lever
Escapement.= A very simple instrument for measuring these angles was
designed by Curzon, one which any watchmaker can arrange for himself,
and is quite sufficient for all practical purposes. This is shown in
Fig. 258, and consists of an ordinary depth tool to which a scale is
added. A hand adapted to the pallet-staff supported between one pair
of runners of the depth tool gives motion to a curved rack (shown by
dotted lines), and this causes a pinion carrying a second index to
rotate, the radii being so related that the movement of the staff is
magnified four times on a scale which can be observed while the glass
is at the eye examining the pallets. The index which travels over the
shorter scale to the left (divided up to 10° on either side of zero)
is connected with the pallet-staff by a fork and a short arm passing
through the circular groove; it affords a convenient means of moving
the pallets while testing them, and gives a measure, in degrees, of
their motion. The graduated arc shown at the top is for measuring the
lever and roller.
=576.= =Verge Pallets: to Measure their Opening.= The little instrument
shown in Fig. 259 may be used for this purpose; its mode of action will
be easily understood from an inspection of the figure.
[Illustration: _Fig. 259._]
One of the pallets being held with its flat face against the base of
the graduated semicircle by the lever and spring B, so that the axis of
the verge is at right angles to the plane of the instrument through the
point _n_, an index previously fixed to the other pallet will show by
the graduations the number of degrees of opening.
This index, shown at P, Fig. 160, must be very light. It is formed in
two parts, the body _c d_, and the small spring _z z_. The pallet when
held in the notch _c_, must have its face held flat against _c d_ by
the spring _z z_. The face _c d_ of the index must be quite smooth and
straight, so as to avoid any error in the reading of the scale.
[Illustration: _Fig. 260._]
The pressure-block C, Fig. 259 (shown in plan and elevation at C, Fig.
260), is movable on its center, and this center, which by an engraver’s
error is represented on the line _n r_, should be a little to the right
of that line.
=577.= =To Open or Close Verge Pallets.= Some workmen cut a notch at
the end of a small rod in which the verge is inserted, the two arms
of the fork being then drawn together by a screw; then, holding each
pallet in a pair of long-nosed pliers, one in each hand, the rod is
held in the flame of a lamp and, as soon as the body of the verge
becomes blue, it is gently twisted to the right or left according as
the pallets require to be opened or closed.
This method is not always convenient, and the following may be
recommended:
[Illustration: _Fig. 261._]
Support the verge by its shoulders between two cone-plate centers in a
pair of finishing turns, as seen in Fig. 261. A carrier _b_ is screwed
to the upper pallet, and prevents the verge from rotating; _c_ is a rod
through which heat is conducted; _a_, shown both in plan and elevation,
is another rod, which is much longer than _c_, and has a notch cut at
the end, so that it can be forced on to the lower pallet. The end _d_
is free, and the =T=-rest shown dotted at _s_, must be brought nearly
into contact with it, the distance between them corresponding to the
angle to which it is required to alter the opening of the pallets.
Now hold a lamp under the free end of _c_ and, as soon as the body
of the verge changes color, _d_ will descend by its own weight until
arrested by _s_, the opening will thus be increased or diminished to
the requisite extent.
The operation will be accomplished more quickly by directing the
blow-pipe flame against the verge body.
Of course when diminishing the opening, the verge must be held in the
reverse direction to that shown in the figure.
CYLINDER.
=578.= =To Polish the Cylinder Lips Mechanically.= The polishing of the
lips of a cylinder is one of the most delicate operations that can be
undertaken by a watchmaker; we have, therefore, endeavored to devise
an instrument by which this can be done mechanically, and which should
at the same time be so simple and so easily made that any watchmaker
should be able to construct it for himself.
[Illustration: _Fig. 262._]
=579.= It consists of two distinct parts which take their place in an
ordinary pair of finishing turns. 1. The plate P, Fig. 262, supported
on a rod T, to take the place of the =T=-rest. 2. The frame E, whose
axis replaces one of the runners. This much being clearly understood
from the figure, there will be but little difficulty in understanding
the following details.
[Illustration: _Fig. 263._]
On the plate P is mounted a bracket, _b b b′_, held by a screw and
washer. It has a slot cut lengthwise, so that on loosening the screw it
can be made to slide towards the right or left. The vertical portion
_b′_ supports a fork-shaped piece, _d c_, a front view of which is
given in Fig. 263, pivoted on a collet-screw, _f_, and this may be
fixed by a pin passing through its end like a bolt. The upper end
of the fork-piece is provided with teeth for a purpose that will be
presently apparent.
The long spindle, _g h_, turns between the two supports, _k_, _l_,
fixed to the plate P, under the action of the handle M. This axis
carries two eccentric cams, _q_ and R. When it rotates, the eccentric R
causes the fork _d c_ to rise and fall, thus occasioning an oscillating
movement of the rack _d_, at the same time the other eccentric _q_
presses against the back of the slide _i n_, which moves freely in the
guide _s_, and is always held against the cam by a helical spring _j_;
the slide thus has an oscillating motion in the direction of its length.
[Illustration: _Fig. 264._]
All the details in regard to the slide and its guide will be easily
gathered from the plan in Fig. 262, and the side elevation in Fig. 264.
A small iron polisher is adapted to the slide _n i_. Being pivoted on
a pin at one extremity, serving as an axis, its end _u_ is pressed
downward by the light spring _v_ (Figs. 262 and 264), which might be
replaced by a spiral spring below the polisher if preferred.
=580.= This being understood, we will pass to the frame E.
The rod that carries it is formed of thick drawn steel pinion wire, the
diameter of which is less than that of the hole in the poppet-head of
the turns. This spindle is provided with brass collars at _y_ and _z_
of such an external diameter as to be received in the poppet-head, in
which the rod can rotate freely. By adopting this arrangement, not only
is the frictional surface diminished, without reducing the accuracy of
the adjustment, but the apparatus can be easily adapted to any pair of
turns.
[Illustration: _Fig. 265._]
To the right-hand side of the frame is fixed, by two screws, the
cylinder carrier _x_ shown at X, Fig. 265. It must be removed in
order to set the cylinder in position by cementing its balance to the
surface; care is necessary to make sure that the back of the cylinder
shall be towards the side _e_ of the frame when the carrier is again
screwed in position. After having thus replaced it, set the rack _d_
to engage with the pinion wire _z_, in such a manner that, when the
eccentric cam R occupies the position indicated in Fig. 263, the small
iron polisher rests at the middle point of the cylinder lip. Now
finally clamp the screw that fixes the support T.
The mode of action of the machine will be easily understood. If, after
charging the polisher with polishing rouge the handle M is rotated,
the cam R will impart an oscillating angular movement to the frame E
through its axis _y z_, and the cam _q_ will, at the same time, cause
the polisher to move backwards and forwards, always in contact with the
surface of the lip during its movement.
=581.= The work will be performed more rapidly, and the polish will be
better if the iron have a slight lateral motion as well as that in the
direction of its length. It is, however, more simple to communicate a
longitudinal oscillating movement to the cylinder, and this answers the
same purpose; it is only necessary to make two small additions, the
spiral spring _o_ and the little cock _a_. The latter is fixed to _d_
in an inclined position (as indicated at A), and this inclination can
be varied by merely turning the left-hand screw. It will be evident
that when _d_ is ascending, the cock will push the spindle _y z_
forward; and when _d_ descends, the spindle will be brought back to its
initial position by the pressure of the spring _o_, which is simply
placed over the end of the opposite runner. This longitudinal movement
must be but slight, and it can be made as little as desired since it
depends solely on the inclination of _a_.
=582.= _Observations._ 1. The angular motion of the frame E must be
sufficient to enable the polisher to act on the entire surface of the
lip. The extent of this movement is determined by the size and the
degree of eccentricity of the cam R. The greatest motion will occur
when the spindle passes through the hole 1 (Fig. 263), and it will
gradually become less as the holes 2, 3, etc., are used. The cam _q_
should also have two or three holes for varying its eccentricity. These
cams may be made of hard wood, ivory, etc.
2. The iron polisher may be replaced by a piece of flexible spring
fixed by a screw to the slide; but its pressure is less uniform.
3. The bent arm _w_, Figs. 262 and 265, is clamped to the plate P by
a screw _d_, and the long arm _b_, Fig. 265, bears against the back
of the poppet-head, and thus ensures the steadiness of P. To insure
steadiness by its means, _b_ is drawn back in the direction of the
arrow, then hooked behind the poppet-head and clamped by the screw
_d_. The firmer the support is the better.
4. The machine may be arranged so that the two lips can be polished
at the same time, but it then becomes more complicated. In the tool
here described, as soon as one lip is polished the cylinder carrier is
unscrewed, turned around, and screwed against the left arm of the frame
E, in which are two screw-holes opposite to those in the right-hand
arm. Unscrewing the slide _b b_, the =T=-rest carrier is moved along
the lathe bar until the polisher is over the lip; _b b_ having been set
in position is clamped, and, after seeing that _w_ has a bearing, the
second lip may be polished.
5. The cylinder carrier shown at X, Fig. 265, is used when the balance
is in position. For a plain cylinder without its balance another form
of carrier is employed that has at the edge of its central hole a small
but solid projecting shell to which the cylinder is cemented.
=583.= _Methods of Obtaining Continuous Motion._ Rapid work is not
possible when a single handle, as shown at M, is used for working
the apparatus; recourse may, however, be had to one of the following
methods:
1. Mount a small pinion with a square hole at its center, and make it
engage with a large wheel driven by a handle. This wheel, having a
great number of teeth, will proportionately increase the rate of motion.
2. Take a powerful clock movement and connect up its center arbor with
the axis _g h_; having wound up the main spring, allow it to run down
so long as it possesses sufficient power to drive the mechanism.
3. Fix a ferule at _h_, and drive it by the aid of a foot-wheel.
BALANCE SPRING.
=584.= =To Select a Balance Spring.= Various methods are adopted for
this purpose. The most common, by which the strength is ascertained
from the length of cone formed by hanging the balance from the inner
coil of the spring while the outer is held in a pair of tweezers. A
more exact method, based on the same principle, is to employ the small
gauge shown in Fig. 266.
[Illustration: _Fig 266._]
A vertical pillar _n n_ is fixed on a smooth plate B, and the slide
C is held by friction in any position on _n n_. Place C so that the
distance between _c′_ and B is equal to the distance between the end
of the lower balance-staff pivot and the balance-spring collet. Having
now fitted the spring in this collet, raise the balance, by tweezers
holding the outer coil, until the lower pivot just rests on B. The
graduations on C will then afford a measure of the extension of the
spring, and this extension should about equal the radius of the balance
measured on the same scale.
When the number of vibrations performed in an hour is known, a spring
may be selected by fitting it to the balance and, while holding the
outer coils in the tweezers, supporting the lower pivot on a hard
smooth surface; the balance is then made to vibrate and the vibrations
are counted. The spring need not be pinned into the collet, but may be
attached by wax to the top pivot.
=585.= =To Fix a Balance-Spring to its Collet.= A common way of doing
this is to put the collet on a wire or broach which is held in one hand
while the other presents the inner end of the spring, held in tweezers,
to the hole in the collet; subsequently fixing it with a pin. The
following is a more convenient method:
At the middle of a brass plate is a boss tapped through a vertical hole
in its center to receive a small screw with flat head. When the collet
is fixed by this screw passing through it, the operation of setting the
spring in position and pinning it will be much facilitated, and the
plate will at the same time afford a means of testing its parallelism.
Two or three screws with heads of various sizes should be provided,
and, in order that they may be always available, they should be screwed
into holes at a corner of the plate.
This tool might be made of further use by adding an arrangement for
holding the stud while drilling it, with a view to ensure that the hole
is at the proper height.
[Illustration: _Fig. 267._]
=586.= =Balance-Spring Gauge.= A back view and side elevation of
this are shown in Fig. 267; it can be made without difficulty by any
watchmaker.
Through the middle of the plate passes a staff _a b_ lightly pivoted
between the cock _p_ and the plate, and projecting on the left-hand
side as far as the point _a_. Between the cock and plate it carries the
collet of the spiral spring _s_ and the stop-finger _d c_, and at the
point _z_ is a light finger _y z_ that passes over the graduations on
the dial.
When the stop-finger _d c_ is free it stands in the direction of the
dotted line _i_; on rotating the staff, by taking hold of the pivot
_a_, in the direction of the arrow _i_, the extremity _c_ of the finger
will be brought round till it presses against the inclined plane _r_,
which it will force back and, on coming against the stop near _c_, it
will be held fast in the notch of the small bent lever that terminates
at _r_. A spring maintains this lever always against a pin set in the
plate. The index finger _y z_ will now be standing over the zero of
the scale, and will be maintained in that position until the finger _d
c_ is released by a momentary pressure of the hand on the push-piece
_n_, when it will fly back to the initial position corresponding to the
dotted line _i_.
=587.= The instrument is used as follows: The small sliding holder
H, which is shown in section at E, (both of these figures being much
enlarged since it is extremely fine and light), has a hole through its
center that fits on to the axis at _a_. Having set a balance spring in
the clip as indicated at E, place H on the pivot _a_, tightening the
slide so that it can be used to rotate _a b_, and bring the stop-finger
round to the position _d c_. Holding the outer coil of the spring in
tweezers at _v_, its inner coil being held in the clip, release the
bent arm by means of the push-piece _n_. The point on the dial at which
the finger _y z_ is arrested will give a measure of the force of the
balance spring _v_.
It will be evident that a spring can now be easily selected of the same
strength as _v_, or stronger or weaker within definite limits which
will become well known when some use has been made of the instrument.
The entire mechanism is enclosed within a box that is covered by a
glass, through the middle of which a hole is made for the passage
of _a_. The spring _s_ is of about the strength ordinarily used for
18-line watches.
[Illustration: _Fig. 268._]
=588.= =To Set a Breguet Spring in Position.= To test the strength of
a flat spiral spring that is to be formed into a Breguet spring, it
must first be attached by its collet to the balance-staff. As the outer
coil cannot be held in the stud owing to its being so near to the pivot
hole, it must be held in the clip _b_ of the little appliance shown at
S, Fig. 268. Holding the watch-plate between _a_ and _c_, the arm D can
rise or fall on the rod _h_, and _b_ can be brought to such a position
that it grips the spring at a point just beyond the stud, so that,
when the spring is turned inward, the point held may be brought up to
the stud. The springing of the watch can thus be proceeded with, and
springs tried until one of the required strength is obtained. It then
only remains to give the spring the double curvature, and to take care
that the end of the overcoil is brought sufficiently near to the center.
Since the action of a Breguet spring is more free than that of an
ordinary flat spring, the watch may be found to lose slightly; it is
advisable therefore to time the watch before making the bend, so as to
show a gain. A little experience will enable the watchmaker to avoid
being much out, and any trifling error that there may be is corrected
either by a displacement of bend or by altering the central coil. If
the latter method is to be resorted to, it is better that the watch
should lose rather than gain a little.
=589.= =To Flatten an Ordinary Balance Spring.= Remove the collet and
stud, and clamp the spring by a central screw between two plates, which
are then placed on a blueing tray and gently heated. A small piece of
whitened steel is laid on the plate in order to see that the heat does
not exceed what is needed to give a blue temper. Allow the plates to
cool and separate them.
Ordinary springs being made of rolled steel and subsequently coiled,
always open out on heating; it is therefore necessary before resorting
to the above method, to coil up the spring, as otherwise the outer turn
will be found to have opened beyond the stud.
=590.= =To Diminish the Strength of a Balance Spring.= Scraping the
end or the entire length always renders the spring defective. Dipping
in acid is very little better. It is preferable to embed the spring in
cork or soft pith, and work it over a ground glass plate covered with
oil stone dust that is fine and smooth. This method might be resorted
to for reducing the height of a mainspring.
[Illustration: _Fig. 269._]
If the cork or pith is hard and only a little metal has to be removed,
the operation is successful; but it is apt to result in more metal
being removed from the edges than from the center. When much has to be
removed, the spring must be cemented to the polishing plate (shown at
G, Fig. 269, and described in article =345=) with fine wax, thoroughly
liquid, so that on pressing the spring all its coils may come in
contact with the plate; it must be held thus until cold. Now adjust the
leveling screws, so that the whole surface bears flat on the glass; rub
it as long as is considered necessary, and detach the spring as soon as
the plate is sufficiently heated; boil in alcohol to clean its surface.
=591.= =To Harden Gold Springs.= Gold detent, thermometer, suspension
and balance-springs can be obtained of a high degree of elasticity.
Rolling hardens them, but renders them very brittle. They can be made
supple and elastic, not by hardening, as in the case of steel, but by
annealing, care being taken not to exceed a certain degree of heat. The
spring may be coiled on a block and placed in a tube that has a smooth
steel lid, then heat the tube in the flame of a spirit lamp, and as
soon as the steel is of a blue temper, remove the flame and allow the
whole to cool.
Others anneal by keeping the spring in boiling oil for a definite
period.
The hardness of a gold spring increases with the proportions of alloy
it contains, and, if well annealed, it will be very elastic and will
break when bent too far, as in the case of steel.
=592.= =To Ease an Index on Its Endstone Cap.= It is a common but bad
practice among watchmakers to scrape the inside of the ring of the
index or to cut it through. A better method is as follows: Resting
the index on a cork, cover the inside of its ring with oil stone dust
and make the cap rotate in its seat by means of a pinion calliper, the
two points of which are inserted in the screw-holes. The operation is
repeated as often as may be required.
DIAL PLATE.
=593.= =To Cut the Large Hole in the Timepiece Dial Plate.= Some
workmen cut the hole in the dial-plate of a timepiece by means of a
strong pair of compasses, one leg of which terminates in a bullet-nose
that is supported in a central hole, while the other is provided with a
hardened cutting point that serves to scrape out a groove.
Others use a rule that revolves on a conical point and carries a slide
with a tracing point which can be replaced by a sharp-pointed cutter.
Proceed in exactly the same manner as when using the compass, but a
greater force can be applied, because, while one hand steadies the
center, the full force of the other is applied to the cutter.
A third and still simpler plan is adopted by some clockmakers. A rod
of the diameter of the central hole, and a cutter of which only the
cutting point projects, are gripped in a vise at a distance apart equal
to the radius of the hole to be made. Then passing the rod through the
central hole and holding the plate in both hands, rotate it, at the
same time applying pressure so as to cause the cutter to form a groove.
When a moderate depth has been attained, invert the plate and cut one
on the opposite side. Care is necessary when the grooves are on the
point of uniting; on the removal of the center, smooth the edge with a
half round file. Some workmen consider it more convenient to set the
cutter and rod in a thick piece of wood that is rounded at the top and
made flat on its two sides towards the bottom, so as to be firmly held
in the vise.
=594.= =To Drill an Enamel Dial.= Take a hard, well-sharpened graver
and moisten it with turpentine or turpentine that contains camphor in
solution, or in the following mixture, which is still better:
Turpentine 62 parts by weight.
Oxalate of potassium 4 ” ”
Camphor 4 ” ”
The two latter substances are reduced to powder and dissolved in the
turpentine, and two parts by weight of sandal wood may be added.
The graver point is placed on the dial at the point at which a hole
is required and the graver is rotated backwards and forwards between
the fingers. Practice, acquired by drilling a few holes in broken
dials, will soon indicate the degree of pressure that can be applied
without fear of accident. Some workmen prefer only to apply the maximum
pressure while the graver rotates in one direction, reducing it during
the opposite movement; others hold the handle or tang in one hand and
rotate the graver with the other, always in the same direction.
The operation is continued, frequently arresting it, however, in order
to set the graver and moisten it, until the copper-plate and back
enamel are perforated.
As soon as this point is reached, take an iron or steel spindle,
pointed at one end. The point must be more obtuse than the hole already
formed in the dial. Charge this end with emery or oilstone dust, and
place in the chuck in your lathe; when the spindle is caused to revolve
the enamel on the contour of the hole will be rapidly removed. When
the copper disc is reached, a fine-pointed and sharp graver must be
used to remove the metal that is exposed as well as that which is
covered with only a thin layer of enamel; then renew the operation
with the spindle, occasionally drawing a file along the surface of the
acting cone. Or the cones of solid emery to be obtained at material
stores can be used for this purpose. A workman must be very careless or
unskilful to fail in rapidly drilling a hole in a dial by this method
without accident, and he may carry on the process easily until the hole
is large enough to permit the introduction of a rat-tail file.
=595.= =To Enlarge a Dial-Hole With a Rat-Tail File.= As an extra
precaution the contour of the hole on either side may be coned with a
spindle as explained above, so as to reduce the thickness of enamel to
be acted upon by the file; but a watchmaker that has had any experience
can dispense with such a preliminary, which we would at the same time
recommend.
The file must enter the hole freely. If only the point can do this, the
file must be held very short, so that the finger may come in contact
with the dial before the larger diameter of the file locks in the hole,
as this would almost certainly crack the enamel. Some workmen avoid
such an accident by forcing on to the file a rather long cork of small
diameter.
With a view to avoid scratching the face of the dial in case the file
is drawn out of the hole in its backward movement, it is well to round
off and polish its point.
During the forward movement a slight circular motion is given to the
file, and in returning no pressure is to be applied; the file must
merely slide over the surface. It is dipped from time to time in the
liquid mentioned in the last article. When the hole is large enough,
a conical spindle should be used to smooth its edges as in the earlier
stages of the process.
=596.= =To Remove Enamel from the Back.= To remove portions of the
enamel from the back when it touches part of the motion work, etc.,
various methods are adopted.
The little spindles of solid emery that may be obtained at material
stores may be used for the purpose.
Some watchmakers use a flattened lead ball perforated at its center and
carried on a taper arbor, forming a kind of small grindstone, rounded
across its rim. The arbor is held in a chuck and the edge of the lead
disc is moistened with water, and emery powder sprinkled over it; when
set in rotation the surface to be removed is held against the lead,
the necessary pressure being applied by the finger against the other
face. Water must be frequently sprinkled on the surface so as to avoid
heating, and to maintain the emery in its place, and the dial is washed
occasionally to examine the progress of the work.
In place of lead, some use emery formed into a solid block with shellac
or various kinds of cement; it is centered on a large taper arbor, and
should be at least a quarter of an inch thick and rounded at its edge.
Such a disc is very hard when cold; it is used in the manner explained
in the last paragraph, but wears more rapidly than the lead disc, if
the latter is well made and supplied with emery of the right degree of
coarseness, in sufficient abundance and evenly distributed.
=597.= =Dials Fixed by Screws through the Edges.= The screw-holes at
the edge are drilled in the manner already explained in article =594=,
and the center hole is enlarged as there described, if this is found
to be necessary in order to permit the free passage of the hour wheel.
The diameter of a dial may be reduced if it is too large in the manner
explained in article =600=. When it has been thus prepared, place it in
position, the XII being exactly opposite the pendant, with the movement
in the case, and close the bezel. If the dial is found to shake under
the bezel it should be fixed with three or four small wedges of
pegwood, care being taken that they do not subject the dial to much
pressure. The accuracy of the position may be tested by holding a
stretched piece of cord over the dial, and observing whether it passes
at the same time through the middle of the pendant, the center hole,
the XII and the VI. When the dial is thus found to be properly placed,
mark one of screw-holes on the watch-plate through a dial-hole. Some
care is necessary in doing this lest the hole is marked eccentrically
or the dial is displaced by pressure against one side of the hole in
it, which might result in the dial being cracked by the screw. Now
remove the plate from its case and drill its screw hole in the drilling
tool; tap it and fit the screw. Replace the plate in the case, and,
after fixing the dial to it with the one screw thus fitted, carefully
mark the second hole, etc.
Some workmen expedite the operation by marking and drilling the two
holes at the same time; but if at first they do not succeed in making
them in the required position they materially increase the time
occupied, as one hole at least requires to be bushed, etc.
=598.= =Dials Held in Position by Feet.= If the dial has feet, and it
is required to adapt them to the plate, they must be first carefully
bent straight; then take a piece of stiff card board of moderate
thickness, and laying it on a piece of lead, punch out with a
sharp-edged punch, or other means, a round hole of the diameter of a
foot. Having inserted one foot in this hole, and placed the card on a
flat surface with the dial uppermost, apply a slight pressure to this
latter so as to mark the position of the second foot. Then punch out a
second similar hole at the point thus indicated. If the operation has
been properly conducted the two feet will enter the holes easily, but
at the same time without constraint or shake, and they should project
on the opposite side.
It now only remains to cut out the cardboard to the size of the plate,
and, after making a central hole and a mark to exactly correspond with
noon, to place it in position in the frame and under the bezel, as
though it were the actual dial. Then mark the two holes for the dial
feet, using a sharp-pointed chamferer that just fits the hole, held
vertical and rotated by one hand, while pressure is applied by a finger
of the other hand.
Some workmen merely prick holes in the card with some sharp-pointed
instrument, or even force the feet through it at all risks; hence it
happens that feet are often bent out of the vertical, and, in order to
be able to bend them into the required position, it becomes necessary
to enlarge the holes in the plate and bend the dial feet.
[Illustration: _Fig. 270._]
=599.= =To Cut a Large Hole in a Dial. To set a Seconds Dial.= This
operation is performed in the ordinary lathe. The hole is cut by a
ring of thin iron or copper cut with saw-like teeth round its edge, as
shown at V, Fig. 270, kept in rotation and charged with fine emery and
oil or water or, what is better, turpentine. The mixture described in
article =594= will secure a still more rapid action.
It is advisable that the thickness of the ring be made to gradually
diminish from _e_ towards _i_, as indicated by the section at S, so as
to prevent it from choking and probably cracking the dial.
The following arrangement may be adopted: Prepare a strong ring with a
projecting internal ridge, shown in section at A B C; cement the dial,
_g d_, to this ridge, or fix it by any convenient means, and attach
this supporting ring to a chuck that rotates in a direction opposite to
that of the cutter, but much less rapidly. On reaching the copper disc,
reverse A B C and repeat the above process on the back enamel. The
copper is thus exposed on the two sides. On filling the deeper groove
with dilute nitric acid the metal will gradually be eaten away, and the
acid should be renewed as often as may be needed. It then only remains
to smooth the edge, beveling it on the front side, and to cement the
seconds dial in position.
The use of acid may be avoided and the cutter passed through the
copper, but greater care must be exercised, because the work is more
difficult when operating on metal. It will, however, not be difficult
after a few trials.
Willis recommends that the dial be cut straight through, commencing at
the back and using emery and oil, the dial being cemented on a brass
block immediately below the cutter, and rather less in diameter than
the hole produced. He mounts the cutter on a stock that is provided
with a pump center, the point of which is maintained throughout the
operation in the small hole or point that marks the center of the hole.
The great advantage of this method is that the taper of the hole is in
the required direction and no filing is necessary.
=600.= =To Reduce the Diameter of a Dial.= Resting the dial in an
inclined position against a block, file its edge with a smooth or
half-smooth file, which must only be allowed to act while advancing,
and is at the same time displaced sideways and turned so as to follow
the contour of the dial. The file should be dipped occasionally in
turpentine, and when sufficient enamel has been removed, pass a new
emery stick over it to remove the file marks.
=601.= =To Remove a Figure or Name from a Dial.= Oil of spike lavender
may be employed for erasing a letter or number.
Enamel powder made into a paste with water, oil, or turpentine, is also
used for this purpose. It should be previously decanted so as to obtain
several degrees of fineness. The powder used for re-polishing the
surface where an impression has been removed must be extremely fine. It
is applied on a piece of pegwood, although some use ivory.
The last and best system is to use diamond powder. Take a little of
the powder, made into a paste with fine oil, on the end of a copper
polisher, the surface of which has been freshly filed and slightly
rounded. On rubbing the marks they will be seen to rapidly disappear.
The surface is left a little dull; it may be rendered bright by rubbing
with the same powder mixed with a greater quantity of oil and applied
with a stick of pegwood.
Watchmakers will do well to try several degrees of fineness of the
diamond powder on old dials.
METAL DIALS.
=602.= =To Restore a Silver Dial.= We proceed to describe several
methods of doing this, but would at once observe that when the
earlier ones are adopted, the hours, if they are painted, necessarily
disappear; whereas they can be retained by resorting to the last method
although great caution must in that case be taken; moreover, it is much
more difficult to accomplish than the others.
=603.= First Method. This is the most expeditious system, and at the
same time the most certain of success.
If the hours are in enamel, there need be no fear; if engraved and
filled with black composition, this will disappear, but it can be
replaced without difficulty. There remains the case of painted hours to
be considered.
First make thin marks with a fine point along the lines of all the
figures, taking care not to pass beyond their ends: and do the same
for the dots and lines that indicate the seconds. By using a glass and
following the instructions given in article =619=, no difficulty will
be experienced in doing this, and the fine lines and dots thus made
will afford sufficient guide for re-marking the hours.
Begin by cleaning the dial with a brush and fine pumice-stone so as to
remove spots and slight scratches.
=604.= _To Frost the Surface._ In order to frost the surface of the
dial, take a spirit lamp with large wick, and direct a blow-pipe flame
from it against the under side of the dial, which is held by one hand
with a hooked support. If the flame is gently directed over the entire
surface of the back, a good dead surface is obtained that resists a
moderate degree of friction either in soaping with a fine sponge, or
washing in a large quantity of water, or in applying soft bread and oil
of spike lavender to erase irregularities or marks made in painting the
figures.
The application of the flame is several times repeated, so as to obtain
a decisive and even frosting; but it is necessary, with a view to avoid
buckling the thin metal, to place an iron or copper washer behind the
dial. The flame oxidizes the surface of the metal; that is to say,
it causes the oxygen of the air to combine with the copper which is
alloyed with silver.
=605.= _Pickling or Bleaching the Dial._ Introduce sufficient warm
water into a suitable flat vessel to completely cover the dial, and
gently pour into it a few drops of sulphuric acid (oil of vitriol), so
that the two liquids are in the proportion of about 1 to 10; then lay
the dial in this dilute acid for a period that varies from half to one
or two minutes. The frosting will first become yellow and then of a
beautiful white color. Wash it in a large quantity of water, wipe with
a fine linen rag, and apply the flame momentarily to the back in order
to prevent the formation of spots on the surface.
When several dials have to be operated upon, the acid is put in a
porcelain dish and boiled by a lamp. Then place each dial for a moment
in it, wash in an abundant suppl of water, and dry by tapping with a
fine linen rag.
=606.= Second Method. For the benefit of such as care to experiment
with it, we add the following method: Brush the dial with a coarse
brush and pumice-stone reduced to an impalpable powder until no
scratches are visible. Make it red-hot and allow to cool. Then dip for
two or three seconds in a porcelain vessel containing dilute sulphuric
acid; on removal it will be found to be white, but rather dull. In
order to produce a clear frosted surface, place the dial in a mixture of
6 parts by weight of nitric acid of 1.22 sp. gr.[8]
21 ” ” sulphuric acid.
50 ” ” water.
Allow the metal to remain in this acid until no more globules are seen
to form on its surface, then withdraw it and immediately place in cold
water. The dial will be observed to be nearly black; it is then pickled
as above explained (=605=), washed well, heated red-hot and, when cold,
again pickled; the operation is concluded by thoroughly washing its
surface.
=607.= _Third Method._[9] Cover the surface of the dial with a thin
layer of soap, and brush it over, taking care to avoid touching the
hours if these are not enamelled. This can best be done with a fine
brush and pumice stone reduced to an impalpable powder. When the dial
has been made as clean as possible by this means, wash it carefully
with water and tartrate of potash (cream of tartar), then plunge
it immediately in the hot solution of nitrate of silver (=608=)
attaching it to the silver wire which is fastened to the zinc and
copper discs =609=; in two or three minutes the surface of the metal
will be perfectly frosted, and, if each operation has been cautiously
performed, the hours will remain intact.
Each time the zinc and copper discs are used they should be cleaned
with nitric acid, and rubbed over with pumice stone. As soon as the
dial is clean, immerse it in the solution; the least delay is apt to
cause the surface to become oxidized through contact with the air.
=608.= _To Prepare the Silver Solution._ Dissolve an ounce[10] of solid
nitrate of silver (lunar caustic) in a small quantity of water; filter
the solution and add twice its volume of liquid ammonia. In a separate
vessel dissolve 6 ounces of yellow prussiate of potash and 4 ounces of
crystallized carbonate of soda in 60 ounces of water, contained in a
vessel of enamelled iron, which must be placed on the fire. When near
the boiling point add the concentrated solution of nitrate of silver,
and allow the mixture to boil for an hour, taking care to add hot water
in sufficient quantity to make up for that lost by evaporation; then
filter the resulting solution.
=609.= _To Prepare the Discs and to Plate._ In order to use this
solution for restoring a dial or plating any other object, take two
discs about the size of a half dollar, one made of zinc and the other
of copper, and, after making a small hole in each, unite them with a
copper wire, or, preferably, with one of silver. After having attached
the dial or other object to this connecting wire, immerse the entire
system in a glass or earthenware vessel, and pour over it a sufficient
quantity of the solution, previously made hot.
If the object operated upon is perfectly clean, bright and free from
all greasy or oily matter, its surface will be found in two or three
minutes to be covered with a firmly adherent layer of silver. When
only a small piece is treated it will suffice to immerse it in the hot
liquor, and rub it with the finger; a bright silvered surface will thus
be obtained.
=610.= =To Clean Metal Dials of Clocks.= When the hours are neither
enamelled nor engraved, it is necessary to first trace out the several
lines and dots in a manner similar to that explained in article =619=.
=611.= _Ordinary Mode of Cleaning the Dial._ Very often it is possible
to make a silver or plated dial of either watch or clock sufficiently
clean by merely brushing with powdered cream of tartar worked into a
paste with water, carefully rubbing around any painted figures with a
fine stiff brush. Then wash with clean water, dry by gently tapping
with a fine linen rag, and expose to a slight heat. (This is in part
the same method as is described in article =607=; the two may be
combined). If the dial is tarnished, it must be silvered as explained
below.
=612.= =To Plate a Brass Dial.= _Preparing the Silver._ Place in a
glass flask from 100 to 150 grains of pure silver made into thin strips
by means of a hammer or rolling mill. Add five or six times the weight
of dilute nitric acid so as to completely cover the silver, and warm
the vessel, taking care to avoid breathing the fumes or admitting them
to the workshop. The metal will be dissolved, and, on continuing the
application of heat until all the liquid is evaporated, crystals will
be found at the bottom. When cool fill the flask with warm water and,
as soon as all the crystals are dissolved, pour the solution into a
porcelain dish, previously half filled with water. Place in it a sheet
of clean copper of about the size of three fingers, and allow it to
remain for the night.
On the following day all the silver will be found attached to the
plate, and it can be collected by immersing this in water. Carefully
pour off the water from the fine powder thus obtained, and wash it once
or twice with an abundant supply of pure water; then dry thoroughly
with the application of very moderate heat. If the silver thus obtained
is not required for immediate use, it should be kept in a dark blue
bottle to avoid the influence of light and moisture.
=613.= _To Prepare the Surface of the Dial._ It must be quite smooth,
thoroughly washed and dried. M. Robert recommends that the smoothing
be accomplished by using soft water of Ayr stone, rubbing in all
directions, in order remove scratches. Or pegwood charcoal can be used,
sloped at one end like a whistle, and applied with water. Others employ
pumice-stone powder and very fine emery paper.
=614.= _To Apply the Silver._ Take equal parts of rock-salt and cream
of tartar, pound them together, and when well mixed, take about 60 or
80 grains of the mixture, and add to it 15 or 20 grains of silver,
prepared as above described, and add a few drops of water to form a
thick paste, which must be well mixed and worked up on a ground glass
plate by means of a horn spatula to remove all grits. A glass pestle
may be used for this purpose.
The dial having been prepared, take up some of the paste with a
perfectly clean and rather stiff brush, and spread it over the surface
of the dial, rubbing quickly and somewhat harshly. The brush should be
worked about in all directions, so as to avoid scratches, until the
silver is found to adhere firmly to the dial. According to M. Robert,
this rubbing is to be continued until the required grain is obtained;
but M. Fournier states that it should be arrested when the surface
possesses a lead-grey color; the dial is then well washed, dried, and
the operation re-commenced exactly as before except that the brush
used is softer. A good surface will thus be formed, and it will be
whiter if the proportion of silver in the paste is increased.
The result attained in great part depends on the skill of the operator,
and this can only be acquired by experience.
=615.= _Observations._ If the mixture contains too much of the salt or
too little silver, the latter will adhere with difficulty, and will
come off in lumps or scales; moreover, it will not have so white a
color.
As the proportion of silver is increased, the white becomes gradually
better; but, on the other hand, if it is in excess the surface will
be coarse and uneven. Too much or too little water will have nearly
the same effect. The color is worse if the dial has been imperfectly
smoothed, and when several days or even hours are allowed to elapse
between the cleaning and silvering.
It is essential that the rock-salt and the cream of tartar be perfectly
pure; if they contain any earthy matter it will scratch the surface and
impair its whiteness.
As soon as the operation is completed, the dial must be washed in an
abundant supply of pure water; any neglect in this particular will
cause it to blacken. This washing may be performed with an ordinary
watch-brush, charged with cream of tartar. Then rinse the dial, and
dry, tapping gently with a fine linen rag, and finish by slightly
warming it.
=616.= =Gold Dials.= It will not be necessary to say much on this
subject. In order to restore the color to a gold or gilt dial, it may
be dipped for a few seconds in the following mixture: Half an ounce of
cyanide of potassium is dissolved in a quart of hot water, and two
ounces of strong ammonia mixed with half an ounce of spirits of wine
and added to the solution. On removal from this bath, the dial is
immediately immersed in warm water; then brush with soap, rinse, and
dry in hot boxwood dust. Or it may be simply immersed in dilute nitric
acid, but in that case any painted figures will be destroyed.
=617.= _Another Receipt._ The following is the method ordinarily
adopted for coloring gold dials; but it is to be observed at the outset
that, although apparently characterized by extreme simplicity, a good
deal of skill is needed to ascertain when the mixture is of the right
consistency, and when the dial has been sufficiently exposed to its
action.
Make a mixture of 4 oz. saltpetre, 2 oz. alum and 2 oz. common salt
(the purest attainable), with a very little water. On placing this in
a blacklead crucible over the fire it will become limpid, and must
be allowed to boil until somewhat pasty and of a pale yellow color,
stirring all the while with a stick. Now take two dials, back to back,
that have been cleaned and blackened by annealing, and pass a platinum
wire through their centers so that they hang horizontally, resting
on a loop at its end; immerse the dials in the hot color crucible,
and, after holding it for a short time, withdraw them and immediately
immerse in a vessel of nearly boiling water standing close by. The
“color” will then be washed, and the progress of the work can be
observed. The dials are again dipped in the crucible if necessary, and
will probably require about three minutes’ immersion in all. It is
advisable that the “color” be thick rather than thin, as in the latter
case the dials are apt to be clouded.
=618.= =To Re-Paint the Hours on a Dial.= The following system has
reference to metallic dials, but the reader will be able to select
without difficulty the parts that are applicable to altering and
retouching the figures on an enamel dial.
We can answer from experience for its being successful, but would at
once observe that it cannot be practised hastily, because some skill
is essential in addition to patience and care: with them, success is
certain.
=619.= _First Method._ Before removing the hour figures and the
divisions for minutes, mark them with a fine steel point, using a lens
and proceeding with great caution. These marks will remain, so that
after the dial has been colored or otherwise treated, it will only be
necessary to trace over them with a fine brush charged with ink.
The short horizontal lines at the top and bottom of each figure, termed
serifs, as well as the two circles that enclose the minute divisions,
can be drawn with a sharpened point of the screw-bar compass.
=620.= _Second Method._ Lay on the dial to be treated, or on another
of the same dimensions that has the hours well marked, a piece of
tracing paper, so that neither it nor the dial can be displaced, and,
using India ink and a fine drawing pen, accurately trace the hour
figures and the minute divisions. When the ink is dry, invert the
paper and trace the figures, etc., thus obtained on the other side of
the paper, this time using a pencil instead of ink. Laying the paper
on the dial so that neither can slip, pass with a rounded point of
some soft metal over all the figures and divisions. Now remove the
paper without permitting it to rub against the dial. If the pencil
has been selected of a suitable degree of hardness, and the operation
skilfully conducted, the marks showing the hours and minutes will be
clearly visible, although faint, and, holding the glass to the eye, the
several marks must be traced over with a fine brush or pencil. If this
operation is performed carefully, the dial will present a very good
appearance.
=621.= _Third Method._ Place the dial within a kind of large barrel
that has at its center a thick pivot projecting. The three rules, D,
F, J, Fig. 271, can be fitted on to this by their central holes so as
to rotate on it. Being supported by the rim of the barrel, they will
pass very near to the surface of the dial without rubbing against it.
From an inspection of the figures it will be evident that D is used
for forming the bars of an X, F for those of a V, and J for that of an
I. Of course the serifs at either end of a numeral are made with the
compass.
[Illustration: _Fig. 271._]
It is unnecessary to observe that if the edge of the rim be graduated,
and the rules terminated by any convenient arrangement for arresting
their motion at the graduations, the hours can be traced on a dial from
which all marks have been erased. It then only remains to paint them in
with ink.
=622.= =Inks for Painting the Hours.= Work up some clean lampblack in
oil of spike lavender. Then add a small quantity of spirit varnish, and
thoroughly mix the whole. This is applied with a fine brush, and the
success of the operation depends very much on the selection of this
latter.
=623.= _Another Recipe._ Mix together ivory black, pure wax, and
turpentine; the more the turpentine is in excess, the more will the ink
be colored. It is best adapted for filling in the figures engraved in
dials, and a gentle heat should be applied to impart a smooth surface.
Any irregularities in the painting may be erased by the aid of oil of
spike lavender and soft bread.
HANDS.
=624.= =To Set a Watch-Hand in Position.= The most delicate part of
this operation is the enlarging of the center hole of a minute hand and
the closing of the hour hand socket when necessary.
Set the hand in cement on a brass plate that has a hole passing through
at the point corresponding to the socket. The hole must then be
enlarged with a semi-cylindrical drill to a diameter such that it will
only be necessary to gently pass the broach through afterwards. The
drill must not be worked too rapidly, and the plate may require to be
immersed occasionally in water, so as to avoid heating the cement and
thus loosening the hand.
When the hole in a watch-hand is too large, it may generally be
sufficiently reduced by means of the staking tool.
=625.= =To Redden Watch-Hands.= Make into a paste (while holding over a
lamp) a mixture of two parts carmine, two parts chloride of silver, and
one part Japan varnish. Having spread some of this over the hands, lay
them face upwards on a sheet of copper, applying heat until the desired
tint is produced.
GLASSES.
=626.= =To Drill Glass.= A hole can be rapidly made in a piece of glass
by using a steel spindle ground at the extremity to a point with three
or four faces, and hardened in mercury. This spindle may be chucked in
the lathe, or rotated between the finger and thumb, the point being
moistened from time to time with turpentine or the mixture mentioned
in article =594=. The glass operated upon should be held against the
blade with the thumb or a pad immediately behind it, and should receive
a gentle rocking motion so as to prevent the drill from choking in the
hole formed; and as soon as the point appears on the other side, the
drilling should be re-commenced from that side. It is a good precaution
to mark the point at which the hole is required with a diamond or the
steel point before commencing, and the pressure applied while drilling
must be but slight.
=627.= =To Cut Glass.= It is possible to cut a sheet of glass roughly
to any required shape with an ordinary pair of scissors, if the
operation is performed under water. Of course a smooth edge cannot be
obtained by such means, but it will often be found sufficient.
A more exact method is to use a piece of ignited charcoal or the
pastile mentioned below, first making a scratch as a starting-point and
holding the heated substance a little in advance of the crack: this
will follow the direction in which the hot body is moved. The method is
available for dividing glass tubes or other objects in irregular shape.
What is known as the “Berzelius pastile” for cutting glass is formed
of the following mixture: Gum arabic, 6 parts; gum tragacanth, 2³⁄₁₀
parts; benzoin, 2³⁄₁₀ parts; lampblack, 18 parts; and the requisite
quantity of water. Mix the gum tragacanth with water and leave it to
swell up for some hours; dissolve the gum arabic in a sufficiency of
water, and powder the benzoin finely. Mix the three, forming a paste of
such a consistency as to be moulded, the lampblack and a little water
being also added. The pastiles are then formed by rolling between two
plates.
The diameter of a watch-glass can be reduced by centering it in a
lathe, chucking it between two pieces of cork or a pair of cork arbors,
and applying a moistened piece of glass to the edge, or an emery
stick. When the desired diameter is attained, polish the edge with
pumice-stone followed by putty powder applied on a wet cork.
BROACHING.
=628.= =To Broach a Hole Vertically.= A hole in a plate, as for
example, that in a barrel, is seldom maintained at right angles to
the surface by young watchmakers when they have occasion to employ a
broach. By adopting the following very simple method, success may be
assured:
Take along cork of a diameter rather less than that of the barrel or
other object operated upon, and make a hole in the length of the cork
through which the broach can be passed. When the cork has been turned
quite true on its end and edge, the broach is pushed through and used
to enlarge the hole; by pressing against the back of the cork it is
kept always against the barrel, and the vertically of the broach is
thus maintained.
=629.= =To Broach and Maintain the Hole Round.= Many workmen either use
bad broaches or work them in a jerky manner so as to make striæ within
the hole. To avoid such distortion when uncertain of the hand, draw
the broach somewhat out of the hole and insert in the space thus left
one or two pieces of hard wood, forming a kind of jacket, so that at
least two cutting edges of the broach may be prevented from acting; the
broach forcing its way into the pieces of wood, will carry them round
with it. A few trials will enable a workman to employ this method.
[Illustration: _Fig. 272._]
When operating on holes that are rather large it is a good practice to
use broaches that are semi-cylindrical or triangular, their sections
being as shown at C, A, or D, Fig. 272. C and D are excellent for
smoothing a hole, but remove very little metal; A does more work
in a given time and, if well handled, will maintain the hole very
round. When operating on a large hole, these broaches can be rotated
in a brace; but, in the case of small or medium size holes, it is
much better to mount them in a drilling headstock like those used by
case-makers for the joint holes, and the tools can be revolved by the
aid of a hand or foot-wheel. Only one precaution need be noted, namely,
the necessity of avoiding the application of too much pressure, so that
the broach jams in the hole.
SOLID AND HOLLOW SQUARES.
=630.= =To File an Arbor or Drift Square by Hand.= The most expeditious
mode of making a square, as, for example, that of a barrel-arbor, is
by using the tool described in article =513=, or one of analogous
construction; but in their absence the square must be made by hand.
Soften the jaws of a hand-vise and make four flat faces on them,
forming an exact square, either by filing or by attaching pieces by
rivets. Having clamped the steel on which a square is to be formed
in the vise, hold this in one hand and rest it in a recess in a wood
block; with the other hand hold the file, determining its position by
laying it on the upper face of the square before applying it to the
arbor. After giving one or two strokes, test the truth of the face
formed by again laying the file on the upper face of the vise. Then
turn the vise through a quarter of a circle and proceed in the same
manner; and so on for the other two faces. Before finishing the square
and while there still remains a slight excess of metal on each face,
ascertain, by examining the end and measuring the lengths of the faces,
whether the square is accurately formed.
[Illustration: _Fig. 273._]
Put in the lathe and draw with flat file in the direction of the axis
along each face. If the square is to be polished after hardening,
proceed in the same manner, using an iron polisher in place of the
file, to which longitudinal, transverse, and circular movements may be
given.
After hardening, the square may be tempered to some shade between
pale yellow and a deep blue, according to the purpose for which it is
intended.
=631.= _Another Method._ Let it be required to fit a square to the
hole in a keyless winding pinion, the diagonal of which is _a′ b′_,
Fig. 273. Turn the end _c d_ of the rod down until it exactly enters
the square hole. Measure with a tapered strip of brass whose edges are
filed sharp the diagonal _a′ b′_; this will give the diameter _a b_
of the larger portion of the rod, as will be gathered from the figure
_a′ d b′ c_.
Turn down the portions of the rod on which the square is to be made and
file four faces, each time arresting the action of the file when it is
on a level with the smaller cylindrical portion, maintaining the angles
equal by observing that the four portions of the circumference retain
their equality while gradually diminishing. By a little care and using
the square-headed hand-vise described above, success may be assured.
=632.= =To Drift a Square Hole in Steel of Moderate Thickness.= The
steel in which it is required to make a square hole must be very soft
and thoroughly annealed, otherwise it is sure to crack under the action
of the drift or when hammered.
To make the hole in the center of a stop-finger, for example, the hole
must first be drilled of a diameter less than the side of the final
square: the drift is then inserted, liberally supplied with oil. On
removing the drift, the square is enlarged by means of a fine square
file acting on each of its corners; then with slightly larger drifts
the hole is gradually increased to the required size. They are driven
with a rather heavy hammer, care being taken to maintain them vertical
and with each change of drift a file should be passed over the surface
to remove the metal that collects at the corners.
=633.= =To Drift a Stem Winding Pinion.= For this purpose the methods
explained above are insufficient, on account of the great thickness of
metal, which we repeat, must always be very soft.
Nevertheless, by using drifts that are very slightly conical, short,
and roughed like a file in an inclined direction, and by using a number
that succeed one another of gradually increasing diameter, steel of
considerable thickness can be treated in the above manner; but it is
far less expeditious than the method explained below.
The piece of steel with a hole drilled through it should be from a
third to half as large again in diameter as it is finally required to
be. After turning the surface true and the two ends flat, the tube is
driven on to a long drift of suitable temper, well oiled and of nearly
the diameter of the hole to be made. Clamping this drift in a hand-vise
or sliding tongs, rest the steel tube on an anvil with its axis and
one face of the drift parallel to the surface, and forge the tube with
a medium size hammer. Turn the drift through a quarter of a circle,
again forge the tube, and so on. Care should be taken that the drift is
forced further into the tube from time to time, oil being at the same
time applied.
A punching machine is also very serviceable for the purpose of
drifting. Sometimes the attempt is made to forge the metal red-hot, but
this is much more difficult on account of the rapidity that is needed
in threading the hot steel, hammering and removing it. Moreover, the
steel has to be heated several times and is apt to be burnt.
If the method above explained, in which the metal is kept cold, is
carefully performed, it succeeds very well, but it must be observed
that steel is often met with that is irregular in composition and
cracks.
TO STRAIGHTEN A ROD, PLATE OR WHEEL.
=634.= =A Steel Rod.= When the rod is short use a large pair of sliding
tongs or a hand-vise, the jaws of which have been softened in order
to make a groove in each parallel to their edge. Placing the rod in
the cylindrical recess thus formed between the jaws, fix one side of
the hand-vise in a bench vise, holding a spirit lamp near the jaws
and, as the steel changes its color, tighten the slide or screw of the
former. When the metal assumes a blue color and the jaws are as tight
as possible, remove the lamp, allowing the whole to cool slowly or by
applying water.
The jaws should be formed so as to bend the rod rather more than
is ultimately required, because steel on being released is apt to
partially recover its initial curvature.
When the rod is long grip its two ends in the frame of a fret-saw,
which should be somewhat strong. Then hold a lamp under the rod, at
the same time stretching the rod more and more, and allow the steel
to remain stretched until quite cold. If it has been sufficiently
stretched the metal will be rendered perfectly straight.
=635.= =A Plate, Escape-Wheel or Stem Wind Wheel.= In the middle of a
square plate that is moderately thick, fit a strong screw with a large
and long head; this screw must pass freely through a disc that is
perfectly flat and fits easily into the upper side of the escape-wheel.
Now fix the plate between the jaws of a bench-vise, and, placing the
wheel between this plate and the disc with a moderate pressure applied
by the screw, hold a lamp to the under side, gradually tightening the
screw as the steel changes color so as to obtain a maximum pressure
when a blue temper is reached. Leave the whole to cool in position.
=636.= =A Verge, Small Arbor or Pinion Staff.= When steel is
sufficiently tempered, it may be laid flat on a smooth piece of copper
held in the vise and flattened by hammering as in the case of an
ordinary rod; but if it is hard the blade of the hammer must be used.
Every watchmaker knows, for example, that a verge is straightened by
striking with the blade against its concave side, while the convex side
rests flat on a smooth anvil. By the action of the hammer the side that
is struck becomes a little longer, thus straightening the staff, It is
not usually necessary to remove the marks left by the hammer, but if
this has to be done the operation should be continued beyond what is
necessary to straighten the metal, then temper it to a blue color and
allow it to cool.
A small smooth taper arbor or pinion staff, can be straightened by
resting it on a wood block, and rubbing the concave side lengthwise
with a worn file of medium cut, applying considerable pressure, the
arbor being firmly supported below to avoid breakage. The result is
the same as with the blows of a hammer, but the marks left are barely
visible.
FOOTNOTES:
[7] It may be well to point out that the above details relate to the
case in which the stem-wind work is on the top plate. When it is under
the dial, of course the corrections here given for a deep and shallow
depth will be reversed.
[8] This contains about 1 part of pure acid and 2 parts of water.
[9] Taken from M. H. Robert’s _Etudes sur diverses questions
d’horlogerie_.
[10] If a greater or less quantity of the solution is required,
all these quantities must, of course, be increased or diminished
proportionately.
CLOCK HAIRSPRINGS.
Repairers’ Assortment. Best Quality, Colletted, carefully arranged,
box containing 50, fifteen kinds, by mail, $1.50
Same Assortment, box containing 100, 2.50
One Dozen for any make of clocks, .50
One-Half Dozen for any make of clocks, .30
Single Springs, .10
If your jobber doesn’t keep them send and get them direct, postpaid.
F. N. MANROSS,
Manufacturer of every description of Clock and Gauge Hairsprings.
FORESTVILLE, CONN.
The American Jeweler
CHICAGO, ILL.
A Monthly Journal for Watchmakers and Jewelers.
As an advertising medium it is unsurpassed. Advertising Rates mailed on
application. Has more =paid subscribers= than any other journal in the
trade.
If in search of a situation or if you want a watchmaker, place your
want ad. in The American Jeweler.
$1.00 per Year. Send for Sample Copy.
GEO. K. HAZLITT & CO.
...PUBLISHERS...
91 Plymouth Place, CHICAGO, ILL.
Eureka Mainspring Winder,
FOR WATCHMAKERS’ USE.
[Illustration: Patented May 25, 1886.]
This instrument is always ready for use, and will instantly wind any
watch spring into coils to fit any American or Swiss Barrel. It is
simple and durable.
Price, Nickel Plated, $1.25.
The trade will find it to their advantage to send us their orders,
as we have the most experienced men, and all orders are filled with
the best quality goods, the same day as order is received, and at the
lowest market prices.
GREEN BROS.
_Importers and Jobbers of Watchmakers, Jewelers and Engravers
Fine Grade Tools, Materials and General Supplies._
11 Maiden Lane, NEW YORK.
THE HARTUNG COMPANY,
211 STATE ST., CHICAGO.
Watchmakers and Jewelers
__FOR THE TRADE EXCLUSIVELY__.
Fine Watch Repairing of all kinds our Specialty.
Demagnetizing. Changing key wind watches to stem wind. Watch case and
jewelry repairing.
All work promptly and carefully executed. Our reputation is of a
good and long standing. We will be pleased to send price list and
information on demand.
CRUCIBLE FURNACE For Manufacturing
Jewelers....
=No. 15. Crucible Furnace.= This will take crucibles up to 4×3½ inches,
holding about six pounds when full, and with ½ inch gas pipe, and a
pressure of gas supplying about 50 feet per hour, will melt a crucible
of gold, silver or brass in about 30 minutes, and the same quantity of
cast iron in about 60 minutes from the time the gas is first lighted.
It is made in a very substantial manner, and is recommended as a
first-rate furnace for manufacturing jewelers, reducing photo waste,
etc. The lid can be lifted away by a handle provided for the purpose.
Prices on Application.
MANUFACTURED ONLY BY
BUFFALO DENTAL MFG. CO
587-589 Main Street,
BUFFALO, N. Y.
[Illustration: No. 15. Patented May 18, 1880.]
Watchmaking
If you want to become a thorough practical watchmaker, you can do so
at less expense and in less time at this school than any other place.
Students received at any time. Send for catalogue and samples of
engraving. Address:
Hutchinson’s Practical School for Watchmakers,
J. L. HUTCHINSON, La Porte, Ind.
SUPERINTENDENT.
Anything and Everything in the shape of
Dials Made to Order from our own
Design or from Yours.
[Illustration]
Dials with Portraits, Monograms, Landscapes, Yachting, Hunting,
Fishing, Polo, Base Ball, Tennis, Cricket, or in fact any design.
SOCIETY DESIGNS A SPECIALTY.
Complete Stock of Plain and Fancy Dials always on hand.
L H. KELLER & CO.
Watchmakers and Jewelers
Tools and Materials
OF EVERY DESCRIPTION.
64 NASSAU STREET NEW YORK.
The Chicago Watchmakers’ Institute
A Modern Trade
School.
Best in America.
[Illustration]
Scientific and
Practical
In all its Methods.
__TEACHES__
Watchmaking and Repairing,
Jewelry Work and Engraving,
and gives a Thorough Course in Optics.
Call and see our school and its work, or send for catalogue.
GEO. D. PARSONS, PRINCIPAL.
913 D, Masonic Temple, CHICAGO, ILL.
WHEN YOU __NEED THE BEST__
Pivot Polishers,
Gear Cutters,
Idler Pulleys,
Hairspring Stud Index,
Crown Chucks,
Turning Tools,
Roller Removers,
Tempering Compound,
Staking Tools,
Pivot Drills,
Pump Drills,
[Illustration]
Or any of the tools you need daily; and when you want the best and most
practical tools, those that have been designed by practical workmen and
proved by them; when you want the latest, best and cheapest tools; send
for circulars and prices to
A. W. JOHANSON,
Manufacturer of Watchmakers’ and Jewelers’ Tools,
_326 Wells Street_ _CHICAGO, ILL._
PRACTICAL BOOKS
....FOR....
Watchmakers AND Jewelers.
FOR SALE BY
GEO. K. HAZLITT & C^o.,
91 PLYMOUTH PLACE, CHICAGO.
=Staff Making and Pivoting.= Practical directions for making new staffs
from raw material. By Eugene E. Hall. Chapter I. The raw material; the
gravers; the roughing out; the hardening and tempering. Chapter II.
Kinds of pivots; their shape; capillarity; the requirements of a good
pivot. Chapter III. The proper measurements and how obtained. Chapter
IV. The gauging of holes; the side shake; the position of the graver.
Chapter V. The grinding and polishing; the reversal of the work; the
wax chuck. Chapter VI. Another wax chuck; the centering of the work.
Chapter VII. The finishing of the staff; pivoting; making pivot drills:
hardening drills; the drilling and fitting of new pivots. Illustrated
with 24 engravings. 48 pages.
Paper covers $ 25
=Watch Repairing.= By N. B. Sherwood. Contents: The Bench and its
Accessories; The Vise and Oilstone; Lathe Appliances; The Jacot Lathe;
Depthing Tool; Expanding the Web of a Wheel; The Spreading Tool and
its Use; The Rounding-Up Tool; Stud Remover; Opening the Regulator;
Roller Remover; Replacing Broken Teeth; Graining Polishing Blocks;
Polishing Steel Work; Polishing Pivots; Superiority of Conical Pivots;
The Cutting Engine; To Cut ’Scape Wheels; Replacing Broken Arbors:
Hardening and Tempering. Illustrated.
Price 35
=The Watchmakers’ and Jewelers’ Practical Hand Book.= A guide to the
student and a workshop companion for the practical watchmaker. Hundreds
of valuable suggestions from private formulas and the best authorities,
together with hints on making certain repairs. An invaluable book for
the workman. The most valuable book for the money ever offered to
the trade. Fifth Edition, Revised and Enlarged. Edited and compiled
by Henry G. Abbott. Illustrated with 154 zinc etchings. 118 Pages.
Flexible muslin, 50 cents. Paper covers
35
=Prize Essay on the Detached Lever Escapement= for watches and
timepieces. A practical and theoretical treatise, by Moritz Grossman,
to which the first prize was awarded by adjudicators appointed by
the British Horological Institute, London. 118 pages, bound in paper
covers, with 20 full page plates, bound in a separate volume. Two
volumes, price,
1 50
=Acme Record of Watches Bought and Sold.= A complete record for dealers
in watches, by which they can at all times tell what watches have
been sold, by whom bought, price paid, profit made, etc., and in case
of the watch being imperfect, the dealer can readily ascertain from
whom he purchased it, or if stolen he has a full description of them
which should materially aid in their recovery. Books of 3,000 Entries,
substantially bound
$1 00
=The Acme Record of Watch Repairs.= A simple and economical method of
recording watch repairs. Book of 1,000 entries, substantially bound
1 00
=The Acme Record of Jewelry Repairs.= A simple and economical method
of recording jewelry and miscellaneous repairs. Book of 1,000 entries,
substantially bound
1 00
=The Acme Watch Guarantee Book.= If you desire to increase your watch
repair business, purchase an Acme Guarantee Book, and advertise the
fact that you “give a written guarantee with all work turned out.”
These books are printed with a stub so that you may keep a record of
all guarantees made, with date, name of owner, description of movement
and case, repairs, etc. They are bound in heavy, substantial covers
printed on good paper and perforated all around so they can be easily
torn out.
Books of 200 Guarantees 1 00
Books of 300 Guarantees 1 50
Books of 500 Guarantees 2 52
[Illustration]
=Abbott’s Americas Watchmaker and Jeweler.= By Henry G. Abbott. An
Encyclopedia for the Horologist, Jeweler, Gold and Silversmith.
Containing Hundreds of Private Receipts and Formulas, Compiled from the
Most Reliable Sources. Complete Directions for Using all the Latest
Tools, Attachments and Devices for Watchmakers and Jewelers.
Among other things contained in this volume may be mentioned a thorough
explanation of adjustments, both to positions and isochronism;
directions for making all the alloys used by a watchmaker, jeweler
and metalworker; a review of all the escapements, their action,
construction and proportion, together with diagrams of each escapement;
an exhaustive treatise on balances, their expansion and contraction,
auxiliaries, sizes and weights and direction for poising; the balance
staff, and full and complete directions for making and replacing
new staffs, together with the use of the graver in turning and
the manipulation of measuring instruments; directions for making
twenty different cements of great value to the watchmaker and
jeweler, including lathe wax; directions for cleansing, pickling and
polishing all kinds of metals: magnetism and the use of the various
demagnetizers; electroplating, bronzing and staining all metals; gauges
of all kinds, and directions for using; soldering and directions
for making all kinds of hard and soft solder and fluxes; steel, its
treatment in annealing, hardening, tempering, etc.; watch cleaning,
repairing, etc.: a treatise on wheels and pinions: directions for
using all modern tools and appliances; and hundreds of miscellaneous
receipts, formulas and hints on all kinds of work, of great value to
every workman. This edition contains forty-four pages more than former
editions, and each page contains one-third more matter than the pages
of former editions. An alphabetical list of over five hundred European
watchmakers who manufactured watches prior to 1800, with years in
which they carried on business, from which the watchmaker can easily
establish the age of any movement that a customer may desire to know
about; an alphabetical list of all books on horology published in the
English or French language prior to 1850; portraits and sketches of all
the celebrated watchmakers of the world from 1600 to 1894. 354 pages.
Illustrated with 288 engravings. Paper covers, $1 25. Fine muslin
$1 50
[Illustration]
=A Simple and Mechanically Perfect Watch.= By Moritz Grossmann. A
Prize Essay on the Construction of a Simple yet Perfect Watch. Written
in a masterly manner by one of the greatest of Horological Authors.
Illustrated with many engravings. From the standpoint of the practical
man at the bench this is one of the most exhaustive essays ever written
on the subject and no practical workman can fail to appreciate it. 96
pages 38 diagrams. Paper, 75c. Fine muslin
1 00
=The Watchmakers’ Library.= This book consists of a collection of the
best articles from the various trade journals of this country and
Europe, among the authors being Moritz Grossmann, M. Kessels, Chas.
Spiro, Chas. Reiss, Herman Horrman, P. M. Youlen, M. Sandoz, Herman
Grosch, James U. Poole, E. Sordet and Vincent Lauer. The papers are all
of a practical nature and of great value to the practical watchmaker,
the whole forming a volume of 290 pages and index. In Paper Covers
1 00
=Prize Essay on the Balance Spring and its Technical Adjustments=
(Baroness Burdett Coutt’s Prize). By M. Immisch. A description of
the invention of the balance spring, its effect upon the art of
watchmaking; the effects of inertia of the balance; resistance of
the air; balance adjustment by means of turning screws and washers;
proportions of spring and balance; nature of spirals; lengths of
balance vibrations and their effect upon the timing; pinning in equal
and unequal coils; the Breguet spring; making its curves, pinning;
regulating isochronal springs, etc. Fully illustrated with numerous
engravings and diagrams. Cloth. Price
1 00
=Repairing Repeating Watches.= By C. T. Etchells. A practical treatise
on the subject and the only one in print. Fully illustrated. The most
vexatious repairs that come to the watchmaker are those on repeating
watches—and yet they are the most profitable if you know just how to
make them. Not every watchmaker can make them, and that is just why
they are profitable. Do you know how? If not, why not? You are never
too old to learn. Paper covers
35
=The Escapements.= Their Action, Construction and Proportion. All watch
and clock escapements thoroughly illustrated and described Illustrated
with twenty diagrams. Paper Covers Price
$ 50
Same in cloth binding 75
=Prize Essay on Watch Cleaning and Repairing.= By F. C. Ries. This work
took the first prize, (offered by The American Jeweler) in competition
with thirty-six other writers. Contents: Examination of the Movement;
Taking Down; Fitting the Dial; Fitting Center Pivot and Bridge;
Bushing; Endshake; Worn Center Pinions; Truing the Barrel; Repairing
the Ratchet; Putting on Square on a Fusee; Examination of Mainspring;
Stemwind Mechanism; Examination of Train; Imitation Gilding; Pivots;
Making Balance Staff; The Hairspring; Jeweling; Cleaning in General.
Price
25
=Watch and Chronometer Jeweling.= By N. B. Sherwood. A complete
treatise on this subject and the only one in print. Contents:
Peculiarities of Gems used in Making Jewels; Requisite Tools and How
to Use Them; Shaping and Polishing the Jewel; Opening the Jewel;
Setting the Jewel; The Endshake Tool; General Hints to the Repairer.
Illustrated. Price
35
[Illustration]
=General Letter Engraving.= By G. F. Whelpley, the acknowledged
authority on engraving. His latest and best work. Contents: General
Hints to Beginners; Lines and Curves; Originality; Practice Material;
Position of Graver; Treatment of Gravers; Correct Spacing; Coffin
Plate Engraving; Necessary Tools; Laying out the Work Preparation of
Plate; Use of Gravers; Methods of Cutting; Slope and Height of Letters;
Inclination of Graver; Transfering; Letters Appropriate for Long and
Short Names; Harmony in Laying Out; Touching Up; Difficult Materials
and their Treatment; Tools and Materials; Sharpening Gravers; Choice
of Tools; Engraving in Rings; Gravers for Same: Engraving Blocks and
Stands: Ciphers, their Formation and Ornamentation; Inscriptions; Best
Manner of Cutting; Ciphers as Compared with Monograms; Monograms and
their Treatment; Figure Monograms or Cipheroids; Intertwining, Complex
Monograms; General Treatment. Copiously Illustrated. 112 pp. Paper
$1.00. Cloth
1 25
=The Watchmakers’ and Jewelers’ Practical Receipt Book.= A workshop
companion, comprising full and practical formula and directions for
solders and soldering, cleaning, pickling, polishing, bronzing,
coloring, staining, cementing, etching, lacquering, varnishing, general
directions for finishing all metals, hundreds of miscellaneous receipts
and processes of great value to all practical watchmakers and jewelers.
This is the only book on the market to-day that gives full and complete
directions for etching names, portraits, etc., in the bowls of souvenir
spoons and silver articles in general. This so-called trade secret
is sold by certain persons at $5.00. Dozens of other “trade secrets”
that are advertised for sale in trade papers at from $1.00 to $5.00
can be found in this book. Worth its weight in gold to any practical
watchmaker and jeweler. 132 pages, illustrated. Paper covers, $1.00.
Fine English muslin binding
1 25
=Poising the Balance.= An Essay of unusual merit. By J. L. Finn 25
=Hairspringing.= A complete treatise on the art of hairspringing. By A.
Z. Price
25
=Adjustments to Positions, Isochronism and Compensation.= The only work
on the subject in print. 50 pp. Illustrated. Price
25
=Repairing Watch-Cases.= A practical treatise on the subject. By W.
Schwanatus. Contents: Repairing the Pendant; Lining Pendant Holes; Work
at the Joints; Soldering the Bezel; The Closing of the Case; Taking Out
the Dents. 40 pp. Price.
25
=Jewelers’ Practical Receipt Book.= Contains a mass of most valuable
receipts, formulas and information, gathered from the best and most
reliable sources. Fifth edition, revised and enlarged. 48 pp. Price
15
=Prize Essay on the Balance Staff and Cylinder.= By P. W. Eigner. This
essay took the first prize offered by the American Horological Society.
Gives methods for turning, grinding and polishing, from staff to
pivots. Illustrated with numerous engravings. Paper covers
25
=Compensating Pendulums and How to Make Them.= A practical treatise
on the construction of mechanically perfect Pendulums, for the use of
watchmakers. By J. L. Finn and S. Riefler. Illustrated. Paper covers,
Price
35
TRANSCRIBER’S NOTE
Illustrations in this eBook have been positioned between paragraphs.
In versions of this eBook that support hyperlinks, the references
to illustrations lead to the corresponding illustrations. Links to
articles have been provided where they are referenced in other sections.
The index was not checked for proper alphabetization or correct page
references.
Obvious typographical errors and punctuation errors have been corrected
after careful comparison with other occurrences within the text and
consultation of external sources.
Some hyphens in words have been silently removed, some added, when a
predominant preference was found in the original book.
Except for those changes noted below, all misspellings in the text,
and inconsistent or archaic usage, have been retained.
Pg 15: removed redundant “to” in “Teeth, to true”.
Pg 28: “horisontal” replaced with “horizontal”.
Pg 29: “emphacise” replaced with “emphasize”.
Pg 29: “an” replaced with “in” ind “one portion removed in order”.
Pg 36: “faciliy” replaced with “facility”.
Pg 42: Caption “Fid. 20” replaced with “Fig. 20”.
Pg 58: “acqua” replaced with “aqua”.
Pg 59: “deterorated” replaced with “deteriorated”.
Pg 78: Duplicate section “88” appeared between sections 85 and 86.
This has been renumbered “85a”.
Pg 102: “phosporus” replaced with “phosphorus”.
Pg 102: Reference to paragraph “666” replaced with “591”.
Pg 116: “cleasing” replaced with “cleansing”.
Pg 117: “cautions” replaced with “cautious”.
Pg 118: “choride” replaced with “chloride”.
Pg 124: “imposible” replaced with “impossible”.
Pg 131: “camporated” replaced with “camphorated”.
Pg 138: Added the word “be” to “The other stones may be
treated in similar manner”.
Pg 139: “dimished” replaced with “diminished”.
Pg 143: “necessary” replaced with “unnecessary”.
Pg 145: “keylesss” replaced with “keyless”.
Pg 147: “expriments” replaced with “experiments”.
Pg 149: “degress” replaced with “degrees”.
Pg 150: “throughly” replaced with “thoroughly”.
Pg 152: Replaced “the” with “to” in “working up towards to
the extremity”.
Pg 153: “sucessful” replaced with “successful”.
Pg 155: “escapments” replaced with “escapements”.
Pg 155: Replaced “too” with “to” in “sealing-wax causes objects
to adhere”.
Pg 156: “bebstween” replaced with “between”.
Pg 156: “especiably” replaced with “especially”.
Pg 160: “magnanese” replaced with “manganese”.
Pg 160: “iatter” replaced with “latter”.
Pg 167: Removed extra “as” in “it is known as a tourmaline”.
Pg 170: “rottten” replaced with “rotten”.
Pg 176: “dazzing” replaced with “dazzling”.
Pg 177: Original text unclear, inferred “taking” in “necessity of
taking care”.
Pg 180: “aquired” replaced with “acquired”.
Pg 189: “ltttle” replaced with “little”.
Pg 197: “calliper” replaced with “caliper”.
Pg 199: “operatar” replaced with “operator”.
Pg 204: Removed extra “be” in “10 feet high may be used as a fixture”.
Pg 206: Replaced “varries” with “varies”.
Pg 208: Removed duplicate “is” in “H is a pipe”.
Pg 209: “ot” replaced with “not”.
Pg 218: Replaced “to” with “too” in “Having too much end-shake”.
Pg 234: “obstuse” replaced with “obtuse”.
Pg 237: Removed duplicate “the” in “raising the edge of a jewel”.
Pg 247: “cuting” replaced with “cutting”.
Pg 251: Replaced “ase” with “are” in “polishers are used”.
Pg 281: Replaced “Illinos” with “Illinois”.
Pg 281: Replaced “Bregeut” with “Breguet”.
Pg 334: Replaced “idex” with “index”.
Pg 341: Replaced “portio” with “portion”.
Pg 345: Replaced “templets” with “templates”.
Pg 348: Replaced “cuttter” with “cutter”.
Pg 357: Removed duplicate “is” in “It is well to have some
change wheels”.
Pg 358: Replaced “It” with “Its” in “Its edge must be saddle-shaped”.
Pg 367: Replaced “late” with “plate”.
Pg 347: Replaced “appplicable” with “applicable”.
Pg 389: Replaced “make” with “made” in “remarks made in speaking”.
Pg 404: Replaced “mannner” with “manner”.
Pg 410: Corrected caption “Fig. 24” to “Fig. 231”.
Pg 418: Replaced end of line “dur-” with “during”.
Pg 422: Corrected caption from “Fig. 338” to “Fig. 238”.
Pg 432: Replaced “characacteristic” with “characteristic”.
Pg 433: Original text unclear, inferred “not to” in
“advisable not to touch the fusee”.
Pg 454: Correction caption from “Fig. 251” to “Fig. 255”.
Pg 463: Removed duplicate “the” from “their heads on the dial side”.
Pg 463: Replaced “escapment” with “escapement”.
Pg 470: “acuracy” replaced with “accuracy”.
Pg 471: “longtitudinal” replaced with “longitudinal”.
Pg 506: “d’horologerie” replaced with “d’horlogerie”.
Pg 511: Added “know” in “Do you know how?”
Pg 512: Replaced “Fuzee” with “Fusee”.Project Gutenberg
The watchmakers' hand book : $b intended as a workshop companion for those engaged in watchmaking and allied mechanical arts
Saunier, Claudius
Chimera65
Academic