Chapter 8 HOW THE WHEELS OF A WATCH GO AROUND

If an electric automobile could be charged in fifteen seconds and then would run for forty hours without recharging, it would be looked upon as a great wonder; but to wind a watch in fifteen seconds and have it run for forty hours is so common that we forget what a wonder it is. When you wind your watch, you put some of the strength of your own right hand into it, and that is what makes it go. Every turn of the key or the stem winds up tighter and tighter a spring from one to two feet long, but so slender that it would take thousands to weigh a pound. This is the main spring.

It is coiled up in a cup-shaped piece of metal called a "barrel"; and so your own energy is literally barreled up in your watch. The outer end of this spring is held fast by a hook on the inside of the barrel; the inner end is hooked to the hub of a wheel which is called the "main wheel," and around this hub the spring is coiled.

This spring has three things to do. It must send the "short hand," or hour hand, around the dial or face of the watch, once in twelve hours; it must send the "long hand," or minute hand, around once an hour; and it must also send the little "second hand" around its own tiny circle once a minute. To do this work requires four wheels. The first or main wheel is connected with the winding arrangements, and sets in motion the second, or center wheel, so called because it is usually in the center of the watch. This center wheel revolves once an hour and turns the minute hand. By a skillful arrangement of cogs it also moves the hour hand around the dial once in twelve hours. The center wheel moves the third wheel. The chief business of the third wheel is to make the fourth turn in the same direction as the center wheel. The fourth wheel revolves once a minute, and with it turns the tiny second hand.

Suppose that a watch has been made with only the main spring, the four wheels, and the three hands, what would happen when it was wound? You can tell very easily by winding up a mechanical mouse or a train of cars or any other toy that goes by a spring. It will go fast at first, then more and more slowly, then it will stop. This sort of motion might do for a mouse, but it would not answer for a watch. A watch must move with steadiness and regularity. To bring this about, there is a fifth wheel. Its fifteen teeth are shaped like hooks, and it has seven accompaniments, the balance wheel, the hair spring, and five others. This wheel, together with its accompaniments, is able to stop the motion of the watch five times a second and start it again so quickly that we do not realize its having been stopped at all. A tiny arm holds the wheel firmly, and then lets it escape. Therefore, the fifth wheel and its accompaniments are called the "escapement." This catching and letting go is what makes the ticking.

A watch made in this way would run very well until a hot day or a cold day came; then there would be trouble. Heat makes metals expand and makes springs less elastic. Therefore in a hot day the watch would go more slowly and so lose time; while in a cold day it would go too fast and would gain time. This fault is corrected by the balance, a wheel whose rim is not one circle, but two half-circles, and so cunningly made that the hotter this rim grows, the smaller its diameter becomes. In the rim of the wheel are tiny holes into which screws may be screwed. By adding screws or taking some away, or changing the position of some of them, the movement of the watch can be made to go faster or slower.

All this would be difficult enough to manage if a watch was as large as a cart wheel, with wheels a foot in diameter; but it does seem a marvel how so many kinds of wheels and screws and springs, one hundred and fifty in all, can be put into a case sometimes not more than an inch in diameter, and can find room to work; and it is quite as much of a marvel how they can be manufactured and handled.

Remembering how accurate every piece must be, it is no wonder that in Switzerland, where all this work used to be done by hand, a boy had to go to a "watch school" for fourteen years before he was considered able to make a really fine watch. He began at the beginning and was taught to make, first, wooden handles for his tools, then the tools themselves, such as files, screw drivers, etc. His next work was to make wooden watchcases as large as dinner-plates. After this, he was given the frame to which the various wheels of a watch are fastened and was taught how and where to drill the holes for wheels and screws. After lessons in making the finer tools to be used, he was allowed to make a watch frame. All this took several years, for he had to do the same work over and over until his teachers were satisfied with it. Then he was promoted to the second room. Here he learned to adjust the stem-winding parts, to do fine cutting and filing, and to make watches that would strike the hour and even the minute. Room three was called the "train room," because the wheels of a watch are spoken of as "the train." The model watch in this room was as large as a saucer. The young man had to study every detail of this, and also to learn the use of a delicate little machine doing such fine work that it could cut twenty-four hundred tiny cogs on one of the little wheels of a watch. In the fourth room he learned to make the escapement wheel and some other parts; and he had to make them, not merely passably, but excellently. In the fifth and last room, he must do the careful, patient work that makes a watch go perfectly. There are special little curves that must be given to the hair spring; and the screws on the balance wheel must be carefully adjusted. If the watch ran faster when it was lying down than when it was hanging up, he learned that certain ones of the bearings were too coarse and must be made finer. In short, he must be able to make a watch that, whether hanging up or lying down, and whether the weather was hot or cold, would not vary from correct time more than two and a half seconds a day at the most. Then, and not till then, was the student regarded as a first-class watchmaker.

The graduate of such a school knew how to make a whole watch, but he usually limited his work to some one part. Every part of a watch was made expressly for that watch, but sometimes a hundred different persons worked on it. The very best of the Swiss watches were exceedingly good; the poorest were very bad, and much worse to own than a poor American watch because it costs more to repair a Swiss watch than an American watch.

Courtesy Waltham Watch Co.

WHERE WATCHES ARE MADE

Once a single man made a whole watch by hand. Now one watch may be the product of a hundred hands, each man doing his particular part.

Even though in America the parts of watches are made by machinery, an apprentice has to undergo just as careful and just as extended training here as in Switzerland. A poor watch is worse than none at all, and careless work would not be tolerated in any watch factory. Of late even Switzerland has been importing American machinery in order to compete with the United States. These machines do such careful, minute, intricate work that, as you stand and watch them, you feel as if they must know what they are about. One of them takes the frame,-that is, the plates to which the wheels are fastened,-makes it of the proper thinness, cuts the necessary holes in it, and passes it over to the next machine, which is reaching out for it. The feeder gives the first machine another plate; and so the work goes on down a whole line of machines. At length the plate is taken in hand by a machine, or rather a group of machines, which can do almost anything. Before they let it go, they actually perform one hundred and forty-two different operations, each bringing it nearer completion. These machines are automatic, but nevertheless they must be constantly watched by expert machinists to keep them in order and make sure of their turning out perfect work.

While one line of machines has been perfecting the plate, others have been at work on screws and wheels and springs. As many of these as are needed for one watch are put into a little division of a tray and carried to another room for its jewels and the rest of its outfit. The jewels, which are pieces of rubies, sapphires, garnets, or even diamonds, are very valuable to a watch. When you know that the little wheels are in constant motion, and that the balance wheel, for instance, vibrates eighteen thousand times an hour, it is plain that a vast amount of wear comes upon the spot where the pivots of these wheels rest. No metal can be made smooth enough to prevent friction, and there is no metal hard enough to prevent wear. The "jewels" are smoother and harder. They are sawed into slabs so thin that fifty of them piled up would measure only an inch. These are stuck to blocks to be polished, cut into disks flat on one side but with a little depression on the other to receive oil, bored through the center, and placed wherever the wear is greatest-provided the purchaser is willing to pay for them. A "full-jeweled" watch contains twenty-three jewels; that is, in twenty-three of the places where the most severe wear comes, or where friction might prevent the watch from going with perfect smoothness, there will be practically no wear and no friction. A low-priced watch contains only seven jewels, but if you want a watch to last, it pays to buy one that is full-jeweled.

And now these plates and wheels and screws are to be put together, or "assembled," as this work is called. This is a simple matter just as soon as one has learned where the different parts belong, for they are made by machinery and are sure to fit. After the assembling comes the adjusting of the balance wheel and the hair spring. There is nothing simple about this work, for the tiny screws with the large heads must be put into the rim of the balance wheel with the utmost care, or else all the other work will be useless, and the watch will not be a perfect time keeper; that is, one that neither loses nor gains more than thirty seconds a month.

It is said that the earliest watches made in Europe cost fifteen hundred dollars and took a year to make. There has always been a demand for a cheap pocket timepiece, and of late this demand has been satisfied by the manufacture of the "dollar watch." Properly speaking, this is not a watch at all, but a small spring clock. It has no jewels, and its parts are stamped out of sheets of brass or steel by machinery. The hair springs are made in coils of eight and then broken apart; and the main springs are made by the mile. Twenty holes are drilled at a time, and the factory in which "dollar watches" were first manufactured is now able to turn out fifteen thousand a day.

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