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Pivoting

From The American Horologist magazine, May 1946

Pivoting

By E. SEIBEL

Pivoting is something that is seldom done these days, but on occasion it becomes a necessity and it must be done. You have a fine watch that has a pivot in bad condition, or you have had an accident with it. In either case, it cannot be replaced or must be delivered sooner than 'replacement can be made.

Now, as to what you can pivot: It is practical to pivot everything, except center upper, and that, under necessity can be successfully pivoted, although you are in constant danger of having it come out when removing the canon pinion. This is true, unless it has been done very carefully and the canon pinion fitted with as easy a tension as possible and still positively carry.

The first points on which to check are your pinion and arbor, to see if they are soft enough to drill. If they are not, draw them to a pale blue, sufficiently down the length, that the drill can go deep enough to enable secure anchoring of the plug. Ordinary pivots should have as much of the plug ,sunk into the arbor or pinion as the pivot is long.

The fourth pivot should be a millimeter, or possibly a millimeter and a half, for 18 and 16 size and proportionately the same for smaller sizes. This is due to the fact that it it carries a second hand, it must not pull {jut when removing the second hand.

The hole that is drilled, must be somewhat larger than the desired pivot. The wire that is fitted into it must be filed to a very slight taper and ground off on the end, so that it will go about one-half to two-thirds the depth of the hole. Then, with slight taps of a light hammer, it must be driven home.

The reason the plug is filed is that the wire is left a little rough from the file and this aids in anchoring it in the hole. It must have only a very slight taper or there in danger of splitting the pinion or arbor. Then you are out of luck! 


In pivoting a balance, the problem is a little more difficult, but it is not as serious as one might think. The only difference is the size. If you should make a mistake on it, you still can, in a great many cases, cut back to the top of the hairspring shoulder and put in a slightly smaller cone than it originally had. You will still have a very good staff and, if it is put in correctly, it will be as good as the original staff.

One thing I must caution you about is, when drilling the staff or arbor, be sure you begin by having them true in chuck or on wax chuck. If your drill should wander a little, don't become too alarmed. If it wanders only slightly, you can still turn a true pivot. However, don't let a job go in which the pivot is so off center (as is often the case) that it can be seen even without a glass. A pivot job can be done in such a way that it is necessary to look with a pivot loupe to see it and many times it is not found, even then.

In drilling, you may have difficulty with your drill. It is possible that your drill may stop cutting. Don't force it! Stop immediately and change the shape of the drill to make it more acute on the point, or make it blunter and put pressure on it-with plenty of lubrication. The thing that has happened is, your drill has lost its edge and has suddenly produced a glazed surface. It is possible you may have to sharpen your drill several times before you are through.

These pivot drills can be bought, but in my opinion, you can make much better ones. It takes patience to make these little drills, but it is worth the effort. In hardening these drills, you must be very careful you do not burn them. Never heat the bit directly but make your shank about one inch long and grasp the extreme end in an old pair of tweezers. Then let the flame of an alcohol lamp hit it midway and allow the heat to run out onto the bit. When you get it cherry fed, quickly plunge it into a cake of bee's wax until it is cold. When cold, carefully withdraw it from the wax and it will be the right temper to do a good drilling job in fairly hard steel.

I forgot to mention the fact that on a square shoulder pivot the broken pivot should be stoned flush with the shoulder. On a balance, merely stone a flat spot on the apex of the cone. After you have this flat spot, center it with a sharp and long-pointed graver for a dead true center. Do not use one with a small teat at the bottom of the center, for this will throw the drill off center.

The width of your center can be checked by taking a new needle and placing the point in the center. Then, rest your finger on the other end and rotate your lathe slowly. If no quivering of the needle is seen, the center is true.


* * *

The Veteran's Administration has announced an agreement with a WATCHMAKING school to help train severely-disabled men in administration hospitals.

The work will be given in seven paraplegic or spinal-cord injury centers, but other severely handicapped veterans will participate, the announcement said.

There are 400 paraplegics in V. A. hospitals with 1,600 more in Army and Navy care to be transferred to V. A. soon, it was tested. One of the paraplegic centers will be at Los Angeles. 


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