If an English arbor, the next step will be to turn the top pivot and fit it into the name plate, and afterwards file the square on the other end of the arbor to receive the ratchet. If, however, it is a Geneva arbor, the square for the stop-work finger-piece must be made, and the lower pivot finished first, and the top or winding square (which also receives the ratchet) last. In filing these squares, great care must be taken to make them really squares. The best plan to ensure success is to turn a line where the square is to end, and file them up in the turns between the centres. The ends of the squares and pivots are usually finished in the screw-head tool. The hook to take the mainspring is formed by drilling an oblique hole in the body, and driving in very tight a piece of good tempered steel, which is then filed to shape. In case of a Geneva arbor with solid ratchet, it is necessary to buy the arbor in the rough, and advisable to have that kind which is half finished, for the body is then screwed on and the ratchet polished.
It is almost impossible to tap a good thread with the ordinary screw-plates suitable for this purpose; and if an arbor not already screwed by the proper plates must be used, it will be found much better to accurately fit on the body with a plain round hole, and secure it with a good steel pin. This latter kind of arbor is generally found where the barrel is " hanging " on the bottom pivot of the arbor, unsupported.
When it becomes necessary to put in a new barrel, as it sometimes does, either from the barrel cracking, across where the " hooking " is, or from unskilful treatment having spoilt it, the best plan is to send the arbor and old barrel to the material dealers, and have a new one of the same diameter fitted to the arbor. The new barrel will require very little finishing, and it is much better and cheaper than Attempting to make one.
A very frequent occurrence is the breaking of the chain, and to repair it neatly and strongly only a small amount of application is required. One end of the broken chain must consist of a double, and the' other end of a single link. It is easy enough, by means of a sharp penknife, to get the single link, but the double one is sometimes more difficult to obtain. The best plan is to rest that end of the chain at which the double link is required upon the filing block, and, with the thumb-nail of the left hand, keep one end of the pair forming the double link tight together, while with the penknife you gently separate the other, so as to loosen the rivet first from one side and then the other. If the chain is then held in the left hand and the small piece of broken link is firmly grasped with the pliers and a sharp pull given, it will be found that the double link is made and ready to receive the single one. When the ends to be joined are placed in position, they should be secured by a rivet made of chain wire; but in the absence of this, a needle, properly tempered to a blue colour, may be used, taking care not to leave the rivet too long. Also remember that the hooks are placed the right way to hook in the barrel and fusee.
When a new chain hook only is required, it will be found much easier to turn the chain than the hook, when the latter happens to lie the wrong way.
When a chain runs fiat, when working back on to the barrel, or slips up the fusee when winding, it must be carefully examined, and the cause found out. Sometimes it results from the chain being too large; then the only remedy is a new chain. At other times it will be found that the delicate spiral projections on the fusee which separate each turn of the chain from the next have become bruised and perhaps broken in places, so that the safe retention of the chain cannot be relied on. If the damage is very serious, the fusee should be re-cut, bat if only trifling, it may be rectified by carefully raising the injured part to its proper position and then placing it in the turns, and allowing a graver of suitable shape held in the right hand to lightly scrape out the grooves as the fusee is slowly turned with the left. When the chain runs off without any apparent cause it may be frequently altered by changing it end for end, or by taking a very little off from the outer lower edge of the chain along its entire length.
When all these means fail, by putting in a new hole for the top fusee pivot, so that the fusee inclines away from the barrel, a certain cure will be effected, as this must evidently cause the chain to run in its proper position.
Fitting Hairsprings is frequently a source of much trouble for the novice. First get to know what train the watch has; this, of course, will necessitate your knowing the number of teeth in the fourth wheel and escape pinion; that is, if it is a seconds watch; if not, you will have to know the whole train from centre wheel. Now if we find the watch has to beat 18,000 per hour, we get the hairspring that will be the proper strength to make the balance oscillate 300 per minute, or 5 per second. This is done by fastening the centre of the spring to one of the pivots with a piece of beeswax; but notice that the centre of the spring has been made the proper size for the collet before being tried, as a spring with its old centre - as made - will be so that it gives its beats slower than when the centre has been broken out to make it fit; therefore when this is correct, and waxed to one pivot, we take hold of the outer coils of the spring, just where the spring is the proper circumference for this coil to reach the same place as the stud and the curb pins.
This will be the proper size, but to get the proper strength, we notice the beats it will make, by placing the other pivot on a watch-glass, holding the tweezers about where it should be pinned in the stud; by giving the balance a slight move we soon see the number of beats it will make in a minute, by counting and watching the seconds hand of the regulating clock.