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.
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Eureka Mainspring Winder,
FOR WATCHMAKERS’ USE.
[Illustration: Patented May 25, 1886.]
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[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:
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[Illustration]
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=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.
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=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
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=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.
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[Illustration]
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=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”.