Chapter XII: Part IV: Tools and Appliances (3)

=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.

=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.

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.

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.

=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.

=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.

=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.

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.

=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.

=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.

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.

=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
-------+---------+------+-------+--------+-------+--------+-------

=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.

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.

=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.

=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.

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.

=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.

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.

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.

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:

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.

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.

=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.

=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.

=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.

=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.