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Closing Train Holes

From American Horologist magazine, April, 1936

Closing Train Holes
By C. Wilkerson
Past President M. W. A. of Colorado

WHEN we repair a watch, one of our objects is to restore the watch as near as possible to its original condition. Proper closing of the train holes, if an unjewelled watch, is an important part of the operation and is a matter not to be passed over lightly.

Some years ago the writer set about experimenting to determine in my own mind what I thought was the most practical and satisfactory method of closing train holes.

One of the objects of the experiment was to determine a method that would preserve insofar as possible, the original thickness of the metal at the holes, and as a result, I adopted and used for this work, a flat faced punch with small hole.

My method of procedure is as follows:
First, before taking movement apart, oil the pivots with a liberal amount of oil. (There is nothing better than oil to loosen old oil.) Take hold of the center wheel and move the train forward and backward a few times. This will loosen the dry and gummed oil on the pivots and in the holes. Then rinse or brush movement in benzine.

You can now ascertain whether or not any of the holes need closing, which should be done before actual cleaning.

The object in using the flat faced punch is that it draws the metal from the sides of the countersink of the plates toward the center and leaves the metal thicker at the hole than would the ball faced punch, which has a tendency to drive the metal away from the hole and leaves the metal thinnest at the hole, the very point where it is needed.

The hole in the punch clears the hole in the plate.

By the use of the flat faced punch I experienced less difficulty in closing the holes evenly and keeping the train wheels upright, whereas, in my opinion, the ball faced punch, unless very carefully used, and even then sometimes will close the hole unevenly.

For best results, the size of the punch must be taken into consideration.

The upper plates or bridges, which have larger countersinks than the lower plate, naturally would require a larger sized punch than would be used on the lower plate with smaller countersinks.

I have three punches which I made especially for this work.

The smallest is 0 MM in diameter.

The largest about 1 MM in diameter.

Larger than this size, I use regular staking punches.

The punches are made on the order of the larger punches, except that they are turned to a smaller point and a small hole drilled.

The smaller punches are very necessary for small work, such as baguettes and other small watches and pallet bridges.

These punches are also very useful for various other purposes, such as closing the hole in a Waltham friction hub, closing jewel screw holes, etc.

As small a punch as practical should be used on a pallet bridge, as a large punch may spread the bridge or throw it out of shape.

For lower center and barrel arbor holes, I use a concave punch.

The holes should be reamed from both top and bottom, producing somewhat the effect of the olive hole jewel.

This I believe eliminates a certain amount of friction and will wear longer than if the hole is reamed from the top only.

When the hole is reamed to the desired size, it should be very slightly countersunk on the underside with a pivot drill, just enough to remove the sharp edge of the hole which will exist after closing and reaming.

This will eliminate to a great extent the probability of creating a burr in the hole when assembling train. It is very convenient to keep at hand for this purpose, a small pivot drill mounted in a piece of peg wood or metal.

Examine each wheel separately as work proceeds and see that each wheel is free and that the endshake is correct, especially the fourth wheel, if watch has a second hand.

Excessive endshake of the fourth wheel will permit the second hand to catch on the other hands.

After cleaning and assembling, take hold of the center wheel and move train forward and backward and examine pivots of entire train with a strong glass and see that all the pivots are free in their respective holes. This can be determined by noting the pivots move a little from side to side as train is reversed.

Avoid closing holes too tight. The train must be free and should back-lash.

A seven jewelled watch of quality, properly repaired is capable of keeping remarkable time. 

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