By Hamilton E. Pease
This would seem a very simple matter, and many seem to think that perhaps it is not important - that it does not matter much if the hands catch and the customer has to bring the watch in two or three times to have them properly adjusted. However, it seems that the average owner of a watch is quite ignorant of its mechanism and that if the watch stops on account of the hands catching, it makes little difference how carefully the rest of the work has been done, the job is unsatisfactory. The careful work that may have been put into resetting the escapement, poising the balance, etc., becomes entirely wasted. I have found that the following steps will eliminate all hand trouble, and all but the last one should be followed each time in assembling a watch.
They really begin with the cannon pinion, seeing that the friction and taper for the hand is right. Then, when the dial is put on, the holes must line up with the center staff and the fourth pivot. Next it is necessary to make absolutely sure that the dial is perfectly tight so that when the watch is turned over, the weight of it will not allow it to touch the second hand, or side play allow it to touch the second hand pipe. Then the hour wheel should be tested to see that it is absolutely free and the taper for the hand is right. It should be carefully tested for sideshake and endshake. I do not make a practice of using dial washer's unless they are necessary. If the top of the hour wheel pipe comes close to the minute hand shoulder on the cannon pinion, no washer is necessary. But if it is a cheap watch with too much space at this point and a considerable amount of space between the hour wheel and the underside of the dial, it is well to put on a dial washer. Now the second hand may be fitted. It should be friction tight when it is pressed on to a level close to the dial, but high enough above it so that light may be seen under its entire length. The watch should be allowed to run for a full minute and the second hand watched carefully to see that it does not touch anywhere on the dial. Although the second hand must be fitted tightly, it should be possible to turn it around to set the watch. It might not be out of place to mention here that in setting up the watch, the endshake of the fourth wheel should have been tested so that the up and down play of the second hand together with its pinion will be the correct amount.
The next step is to put on the hour hand. This should have a tapered hole to conform with the taper of the pipe, so that when it is pressed into place it will be rigid and not have a tendency to rock from side to side with the slightest pressure. The freedom of the hour wheel should now be tested again, as an hour hand put on tightly will often contract the hour wheel tube and make it bind although it was perfect before fitting the hand.
Next the hand should be adjusted to run as close to the second hand as possible, allowing for a safe amount of clearance, the test always being made with the second hand raised as high as the endshake of the fourth wheel will permit. The hour hand should be straight and parallel with the surface of the dial its entire length. The watch should be set around so that the hour hand will travel over the entire seconds bit, as a great many times an hour hand will be all right in one or more places, but the wheel carrying it will allow it to dip down onto the second hand at other places.
The minute hand may now be fitted. With most high-grade watches this should be pressed down on the cannon pinion as far as possible, but one must use his judgment on the individual job, as on some cheap watches it must be pushed only part way on to allow sufficient endshake in the hour wheel and hand. It must be carefully tested to make sure that it is absolutely tight. Some minute hands have become very slightly loose from being taken off and put on so many times, and can be made secure by just tapping lightly on the bottom with the three cornered punch. This hand also should be' straight excepting at the end, and there it should be curved down to conform to the curve of the crystal.
The watch should now be turned dial down over a mirror for the purpose of watching the hands, and be set.