Rules and Practice for Adjusting Watches

by Walter J. Kleinlein

It is advisable to always have the flat true as by doing so any slightly bent pivots will be detected through wavering of the balance and the flat is not very frequently affected by setting of the metals.

Balances should generally be trued and poised in normal or slightly above normal temperature. If they are trued in a low temperature they will be out of true and possibly out of poise in the temperature to which they are mostly subjected. Compensation balances are not presumed to be true in the round under variations of temperature and therefore inspection for true is necessary in somewhere near the same temperature in which they are trued.

[81.]Poising the Balance.

In poising balances it is necessary to consider the mean rate of the watch and several details in connection therewith.

If the rate is known to be fast, weight should be added to the light side, and if it is known to be slow weight may be removed from the heavy side.

If the rims of the balance have been trued outward it is a safe rule to remove weight from the heavy side in poising and if they have been bent inward to get the balance true, weight should be added to the light side in poising.

A balance that is in perfect poise can be brought to a perfect stop on a fine jeweled poising tool at any point of its circumference. For ordinary work it is generally considered as satisfactory if it can be brought to a perfect stop at each of the four quarters. When the heavy point seems to be first at one place and then just opposite it is proof that either a pivot is bent or oval in form instead of round.

In some instances balances will be found to swing slightly and stop at several different places. This is usually an indication that there are several flat places on one or both pivots and if the watch is a fine one the staff will require changing or the pivots may be rounded up on a Jacot Lathe. A fine edge jeweled poising tool is best for fine work as defects in pivots and variations in poise can be more easily discovered than with calipers.

[82.]Truing Hairsprings.

Original truing of the hairspring is made necessary by the fact of attaching the collet to its center. When springs are turned out by the manufacturer they are perfectly true, that is, the coils are level and perfectly spiral in form and the deviation from this spiral form, made necessary in attaching the collet, is what demands certain forming of the inner terminal so that it will blend with the other coils of the spring which have not been disturbed.