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Watch Repair - Barrels, Fusers, Mainsprings, And Chains

( Originally Published 1918 )



Broken Mainsprings. — A mainspring that is broken close to the outer end may be made to do again by punching a fresh hook hole and filing up. First soften the extreme end in the spirit-lamp flame, and hammer it flat. Then, with a mainspring punch, or an ordinary flat-ended round punch, and a graduated steel stake, punch a hole in it. A round hole is as good as any. Broach out the hole aslant, as in Fig. 72, so as to leave a sharp edge outside to hold well under the barrel hook. With a rat-tail file open the broached hole oval and make it quite central. Then flat the spring end on both sides by filing to remove all burrs, and shape the end up as in Fig. 73.

This is the usual method of hooking a spring in its barrel. But there are many others. The old way was to rivet a square block of steel into the spring end and cut a corresponding hole in the barrel to receive it. To make such a hook, take a length of oblong drawn "hooking-in " steel of the correct size, and screw it in the vice aslant, as at A (Fig. 74). File it up as at B, leaving a kind of pivot to rivet into the spring. Cut it off as at C. Hold it in a pair of cutting nippers, and file the surface flat where cut off. Then rivet it in a hole punched in the spring ready for it. The spring end in this case should be filed up as at D, and the pointed end thinned. The block is finally finished off smooth, so as to lie level with the outside surface of the barrel.

Some springs are fastened in with a brace or buckle, like Fig. 75. These braces can be bought ready made, by the gross, or they may be made from a short length of thicker and wider spring. A home-made one requires a hole punched in it and the spring, and a brass rivet to hold all together. The bought braces have a soft steel rivet on them ready for riveting into the spring. The two pivots of the brace go into holes in the barrel bottom and cover, and allow the spring to draw over when wound full up instead of bending. This system is used in all American and many English machine-made watches.

A method used in cheap Swiss watches is shown in Fig. 76, at A. The extreme end of the spring is softened, and turned back.. A short loose piece of spring is slipped in, sharpened at one end to catch on the hook. When the turned back end reaks off, as it often does, the average repairer finds a great difficulty in turning another without breaking it. A way out of the difficulty is to rivet a short piece of spring on, as at B, with a brass rivet. To punch a hole in the end to go direct on to the hook is, as a rule, no good in these watches, as the hook is not of a shape to allow it to hold properly.

When a mainspring is broken in the " eye," or anywhere in the middle of its length, a new one must be fitted. There are two things to consider in selecting a new spring. It must be of the right width and strength. Before pulling the old spring out, see if it is of the correct height or width. It should reach nearly up to the groove in which the cover is snapped. If correct, measure its width in the gauge, and take the packet of springs indicated by the gauge number. To measure the strength, the gauge shown in Fig. 77 is used. Pick out one that matches the old spring. In a mainspring thickness means strength. Two springs of the same thickness are of the same strength. Yet a "dead" spring will not pull like a lively one. In Fig. 78, A shows a good lively spring ; B indicates a dead one. A spring that has been once wound in a barrel and comes out like B will not pull a watch as well as a much weaker one that comes out like A. " Life " in a spring is a question of quality and temper.

Measure the length of the new spring by the old one roughly, leaving it a little too long. Wind it in the barrel with a mainspring winder, and see if it is of the correct length.

Fig. 2, p. 2, shows about how full the barrel ought to look. If more or less than this, the spring will not give so many turns. The outer end can be broken off with the fingers until correct. Then soften the end, hook as before described, and finally wind it in.

To wind a spring in with a mainspring winder requires some practice. Hook the eye on the arbor of the winder, wind up a turn or so, holding the spring in the fingers of the left hand. Then place the barrel over as many coils as it will cover, and press it against the end of the winder arbor. Continue winding, guiding the spring in with the fingers and holding the barrel firmly. When all is in, it will hook itself, especially if pressed well down and given a turn or two more.

A spring having a reverse end like Fig. 76, B, or a brace like Fig. 75, is best put in by hand. To do so, put the outer end in first, and coil it in gradually, a little at a time, without straining the spring. Finally, press it well down with a screw-driver, and the brace can be pushed round into its place by the same means. A reverse end will go to its place and catch properly the first time it is wound.

There are many gauges of mainspring widths, mostly based on the millimetre. In one gauge No. 1 is mm., No. 2 2/10 mm., and so on. In another gauge No. 1 is 1 mm., No. 1 1/10, and so on. Using either of these gauges, the sliding millimetre gauge with vernier reading to tenths can be used to measure them, and also to measure the depth of a barrel, and see at once what number of spring is required. In posting for a single spring, it is only necessary to enclose an inch of the old one which it is to replace.

Barrels.—If a mainspring breaks in the barrel of a fusee watch, when the spring is nearly wound up, it often expands it so much that the cover is loose, or even makes it so cone-shaped that it will no longer go in the watch. The cause of mainsprings breaking is obscure. They break more often when undisturbed than when being wound up. A change of temperature seems to affect them, and on such occasions watches with broken springs come in to the repairing shop in half-dozens. Often a spring will break into three, four, or up to twenty pieces. Exactly what occurs at the moment of breakage in such cases is an interesting speculation.

When the cover is loose it can be tightened by spreading the edge equally all round with a hammer. Lay the cover, underside uppermost, on a flat, polished, steel stake. Begin at the notch and gently tap it all round with the flat of the hammer until the notch is reached again. Be very careful to hammer flat and not dent the cover. Hammer aslant to spread the edge, moving the hammer in the direction shown.

A barrel spread too much to go in the watch may be closed with care by using a jeweller's ring-stretching tool.

To put in a new barrel hook, drill the barrel centrally, and broach it slanting a little in the direction to hold the spring. Tap the hole with a good full thread. File up a taper hard brass pin, thread it in the screw plate, cut off its end, and file it a little slanting. Then screw it in from outside until it jams tight. If too long inside the barrel, withdraw it and shorten. Leave just sufficient inside the barrel to come well through one coil of the spring. Finally, cut off the pin outside and smooth off. The success of this method depends on jamming the pin tight in the barrel, and to aid this the hole may be tapped a little small by not running the tap more than half its length in, and the pin may be tapped as full as possible.

Very good ready made hooks can be purchased at the material shops. They are made with a long tapered end that can be passed through from the inside of the barrel and screwed outwards until tight. The outer tapered part can then be cut off level and smoothed. These hooks are better than those screwed in from the outside, as they cannot be forced out by the breaking of a mainspring.

A barrel that is burst cannot be repaired. It is no use soft soldering it up. A new barrel and cover can be bought from the material shop, in the rough. First open out the cover to go tightly on the top pivot of the arbor. This can be done by broaching. Then turn the inside boss; A, down until the shoulder of the pivot comes through the cover, as at B (Fig. 80). Serve the barrel bottom the same and fit it to the lower pivot, thinning the inside central boss until the cover. endshake of the arbor inside the barrel is right. All this turning work is done very easily in a lathe, holding barrel and cover in step chucks and using the slide rest. In the turns the cover and barrel B, A can be put on arbors and turned by hand; or they can be done in a mandrel. To make the chain hook hole, put the barrel in the frame and mark a line on the barrel just below the under edge of the top plate, so that the chain will just touch it if drawn straight away from the hook hole. With the pointed chamfering tool dot two drilling centres, as shown in Fig. 8. Drill hole No. 1 through slanting, as Hook Hole. shown at A. Drill hole No. 2 still more slanting, as at B. Then with a pivot broach and oil broach one into the other, as shown at C. This makes a good oblong hole, well undercut for the hook. Put in a good sound mainspring hook. For a finish, buff the barrel round with a 3/0 emery stick, and finally with a dry rouge-on-leather buff. The cover may be served the same, or it may be stoned with water-of-Ayr stone and water by short circular strokes round and round all over it. Barrels are best not gilt, as gilding softens them.

A mainspring that binds in a barrel when running down may sometimes be eased by getting its coils flat. Or, if the cover is a thick one, it may be put in a step chuck and a thin cut taken with the slide rest from the centre boss nearly to the edge. If a spring binds much a new one makes the best job.

An arbor that has no endshake in the barrel may be given some by laying the barrel over a hollow turned out in a piece of sheet brass and giving the top of the arbor a blow with the hammer. This slightly bulges the bottom outwards. If a barrel is too high in the watch, it can be lowered by bulging the cover up in this manner and the bottom up also. Similarly, a barrel can be raised if required. For these operations a "doming stake" is useful. This may be made of a piece of sheet brass 1 in. square and 3/16 in. thick. A in. hole is drilled in its centre and a shallow coned hollow turned around it, about 1/16 in. deep and of a diameter equal to the barrel of a lady's watch.

A watch barrel sometimes runs foul of the top bar in an English watch. To remedy, the bar is centred in a mandrel or lathe by the barrel pivot hole, and a cut with the slide rest taken across its underside from near to the centre hole to beyond the edge of the barrel.

Going barrels are generally made stronger than chain barrels, and seldom either stretch or burst; but when a spring breaks it often bends a tooth—the one that happened to be in the centre pinion at the time. These can be straightened by putting a screwdriver blade or a pocket-knife blade between the teeth and levering the bent tooth up. A broken barrel tooth is best replaced by drilling into the barrel, tapping the hole, and screwing in a steel pin, which is then filed up to the length and shape of the other teeth.

A new steel hook can be put in a barrel arbor by drilling a good deep hole into it in a fresh place and driving in a steel pin. This is then filed up and undercut to hold the eye of the mainspring.

Fusees and Chains.—In fusee watches the chain often breaks. To mend a chain, lay it on boxwood and hold the end link down with the finger nail, while a thin-edged pocket-knife is used to open it and start the rivet end. As soon as the side of the end link is raised enough to clearly show the rivet, get a steel needle and flat its end slightly on an oilstone. Screw the needle in a pin vice for a handle, and, placing the chain with the rivet over a small hole in the steel stake, push the rivet through with the needle. If stubborn, tap the pin vice with the hammer. In this way prepare both ends of the chain, leaving a double link to one piece and a single link to the other, as in Fig. 82.

For pushing out chain rivets and similar jobs the long pins sold with round glass heads are useful, as they can be used comfortably in the hand.

File up a tempered steel pin (a needle let down to a blue), and place the two ends of the chain together so that the hooks at the ends come on the same side. Insert the pin, still in the pin vice, and tap it in gently over the stake. With nippers cut the end off flush, and with a very fine file, file it flat with the chain. Cut off the other end of the rivet, lay the chain on box-wood, and file both sides flush with the chain. Then lay the chain on a flat steel stake and gently tap the rivet on both sides. The join, when done thus, should be invisible.

If the chain on a partly wound up watch falls flat upon the barrel, take a graver, stick it in the barrel edge, and force the barrel back a little to ease the pressure off the chain. It will then usually fly up into its correct position. If a chain persists in turning over in this manner, reverse the hooks; that is, put the fusee hook on the barrel end and the barrel hook on the fusee end.

When the fusee groove is bad, there is no remedy but sending it to a fusee cutter (the material dealers get such jobs done), together with the chain, and having it re-cut to fit.

The winding work inside a fusee often needs repair. To take it apart, hold the square in a pair of sliding tongs and push out the pin that goes through the steel cap underneath. The cap then comes off, the main wheel and maintaining ratchet following. The ratchet is then seen, and also the clicks. To fit a new ratchet, first lever up the old one with a pocket-knife ; it is pinned on with two brass pins. Pick out a new one to pass easily inside the clicks; gauge this by laying it on the maintaining ratchet and observing the clicks. Open out the centre hole by broaching until it goes tight on the fusee arbor down to its seating, the old brass pins having been cut off level. While broaching the ratchet, hold it in a duster in the fingers only. Mark and drill two new pin holes through the ratchet deep into the fusee body. File up and drive in two brass pins. Cut them off level. Then put the fusee by its top pivot in a split chuck in the lathe and turn the pins off flush. Also turn out the centre of the ratchet like the old one, cutting out a complete ring around the arbor. This space is to accommodate the centre boss of the maintaining ratchet. If the new ratchet is so thick as to stand up above the edge of the fusee body, thin it by turning while in the chuck.

In a pair of turns, to centre a fusee properly, a "fusee arbor" is required. This is an adjustable holder in which the fusee square is held and admits of being centred truly by adjusting screws.

A broken fusee click must be first removed by placing the maintaining rachet over a hole in a stake and punching it through from underneath with a small flat-ended punch. New clicks are made from f0 click steel." This is steel rod, drawn to the section of a click, like Fig. 83. To make a click, screw the length upright in the vice, leaving a small piece standing up above the jaws, as at A (Fig. 84). Resting the safe edge of a pillar file on the vice jaws, file round it, leaving the pivot as at B. File the pivot up, without removing from the vice, until it goes' nicely and easily into the hole in the maintaining ratchet. Then remove the length of steel, and with a slitting file saw off the click, as marked at C. Hold it in a pair of cutting nippers and flat the rough sawn surface with a file. Then place it in position and rest it on boxwood, click down, and file off the projecting part of the pivot. Transfer it to a flat steel stake, and with a round-faced punch slightly rivet its end into the countersink of the hole, taking care to only rivet sufficiently to prevent it coming out and not enough to tighten it. It must be perfectly free. If riveted a little too tight, it must be placed over a larger hole in a stake so that no part of the click is supported, then a tap given to the under-side of the riveted pivot will ease it; too heavy a tap will drive it through. When correct, lay it, click upwards, on boxwood or cork and file the top down level with the other dicks and the springs. In doing so carefully avoid filing anything but the click. Finally, cut the file burr off all round the edge with a sharp graver.

Fusee stopwork sometimes is troublesome. The stop A, Fig. 85, sometimes sticks up close to the plate, and will then stop the winding at every turn of the fusee. It should be perfectly free in its joint, and the pin must fit tight in the brass joint and loose in the stop. The slender spring should be in its place and carry the stop away from the plate promptly. This stopwork is designed so that when the chain reaches the top and last turn of the fusee it raises the stop A to the plate and the projecting finger on the fusee comes into contact with its end. The end of A should be flat, not notched or sloped, or the fusee finger may slip off it. If the watch overwinds, first ascertain if the fusee finger passes over or under A. This done, if it passes over A, bend A up a trifle so that it rises more quickly, if under, bend A down. Brass-nosed pliers should be used for bending.

The maintaining detent often fails to properly catch the teeth of its ratchet. If so, file its point up nice and sharp. If it slips up over the teeth it can be bent down with brass-nosed pliers while in the plates. If the fusee is pinned up too tight the maintaining work will not act. Copper wire should always be used for pinning up a fusee, as it is soft. If too tight, hold the main wheel in the hand and hit the bottom fusee pivot with a hammer, hard. This will slightly bend the copper pin and ease the fusee work. The interior of a fusee should be well oiled.

Safety Pinions, etc.—All English watches of a few years ago had fusees, and consequently wound to the left. In fact, this winding to the left got to be the distinguishing mark of an English lever with the general public. If a watch wound to the right it was at once put down as foreign. Some makers of English going-barrel watches, therefore, go to the pains of making them wind to the left, and to attain this end—merely to pander to a popular error—introduce a large dummy wheel, or idle wheel, between the going barrel and the centre pinion. Others introduce a pair of steel winding wheels under the dial, which are 'generally the cause of very rough and bad winding. Of the two the dummy wheel is to be preferred, as it only wastes a little power. But a plain going barrel, winding to the right, is better than either. It is claimed that the dummy wheel acts as a buffer in case of a broken mainspring, and takes off the shock from the centre pinion. If it does so at all it is very little, as watches so made are frequently found with broken third wheel pivots and bent teeth after such a breakage. The proper way to avoid these injuries is to use a safety pinion.

Some American watches have a safety barrel instead, which acts just as well. In them the barrel is of steel and is separate from the main wheel. In winding the watch the steel barrel is turned round. If a spring breaks the barrel receives the shock, and, being separate from the main wheel, the train escapes. These steel safety barrels are a little awkward to put hooks in. Very good fitting steel hooks must be fitted, and left as short inside the barrel as possible.

Clickwork.—Some English going-barrel key-wind watches have very bad winding work. The click is often only held by a small chamfer-headed screw (Fig. 86, A) which, when screwed home, holds the click tight so that it sticks, and to allow the click to work easily, must be left loose. This loose screw is in constant danger of working out. The remedy is to broach out the hole in the click parallel and then screw a fixed brass stud into the plate for it to work upon. The stud can be drilled in its centre and a flat-headed screw fitted to hold the click down, as at B, or a small brass covering cock may be made instead.

A new steel winding ratchet or a new click to these watches should always be hardened and tempered.

Bar Geneva watches have " side clicks ;" that is, click and click spring made in one and screwed to the side of the bar, as in Fig. r, p. r. When these fail to hold, file up the ratchet teeth, point up the click, and let it into the bar deeper by filing away the brass a little where required. A ratchet that has many broken teeth or that is badly worn necessitates a new barrel arbor to make a good job. But a makeshift can be arranged by turning off the ratchet all but a thin flange to hold in the bar, and fitting a loose new ratchet, carefully opened out in its centre hole to drive tight on to the square.

Three-quarter plate key-wind Geneva watches usually have circular click springs, as in Fig. 3, p. 3. When one is not readily obtainable of the correct size, a brass one can be easily made, and, if well hammered, is as good as steel.



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