CHAPTER XVI

SPECIAL NOTES

79. _Efficiency of Execution a.n.a.lyzed (Two Examples)._

In performance of the various alterations and corrections that have been touched upon in the chapters devoted to position adjusting there are some points that deserve special note. This refers to positive execution of the correction which the watchmaker sets out to make.

As an example we may a.n.a.lyze the simple feature of polishing a pivot and cleaning and reoiling a jewel to improve the motion in one of the horizontal positions. Ordinarily this would seem to be a very simple proceeding requiring no additional remarks.

It is, however, quite possible to go through all of the operations of removing, cleaning and reoiling the jewel and polishing the pivot and then find that no improvement has been made in the motion.

Invariably the workman of moderate experience will say that he has just cleaned and reoiled the jewel and polished the pivot and that it must be all right.

Investigation, however, will sometimes show that the pivot has again been marred or that a particle of dirt has found its way into the jewel hole during replacement either through dust in the oil or through clinging to the end of the pivot when the balance was laying on the bench.

This experience is one that comes occasionally to the best and most careful adjusters and if it is found that results have not been obtained the first time it will be necessary to go over the operations a second time.

It is possible to almost entirely eliminate this duplication of work if proper care is exercised in examining the pivot and jewel with a good gla.s.s before replacing and in using oil from a closed receptacle in which it has not been possible for dust to collect.

The point raised in this instance is that the improvement desired is not a.s.sured because of merely going through the operations of doing the work.

It is necessary to actually remove the cause and then keep it removed.

The proof is found in the improved motion and it would hardly be worth while to retest in positions until this improvement was obtained.

Proper curvature of the over coil within the range of the regulator pins is another feature that may be corrected and the correction unconsciously destroyed in replacing the balance or in centering the spring.

A slight kink in the coil close to the regulator pins may cause the spring to be forced out of center when the regulator is moved, or it may cause the coil to lay against one pin and cease vibrating between the pins. This would cause a gain of some seconds per day when the regulator had actually been moved to cause a slower rate.

These two examples are introduced to convey the idea that it is necessary to actually produce the corrections or alterations in any instance and that close timing and close position rates depend more upon this practical execution and understanding as displayed by the watch repairer than they do upon a high degree of technical knowledge.

Personal instruction of watchmakers in adjusting has demonstrated in most instances that the refinements are not considered seriously enough at first, but that consistent practice and reference to the rules soon make the proper impression, after which results are attained in less time than was at first required for faulty execution.

80. _Truing the Balance._

The balance should invariably be true in the round and flat and always in poise before it is placed in the watch.

It is at times pardonable to pa.s.s a balance that is not perfectly true in the round, especially when the watch has been repaired on several occasions and it is noted that the rims have a tendency to become set slightly inward or outward after having been perfectly trued. This shows a natural tendency of the metals to find a permanent position which may be slightly away from the true concentric form. A balance of this description may be poised as it is and often will produce better timing results than would be gained by perfect truing and subsequent regulation during readjustment of the metals.

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 circ.u.mference. 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.

In attaching the collet it is first necessary to have the spring level before the pin is forced tightly in place. This can be fairly well determined by sighting across the flat of the spring and focusing upon the inner coil to see that it is level for at least one half of its length from the point of exit. After this operation has been completed and the pin has been set up tight, with the surplus ends cut off flush with the collet it will be necessary to slightly pull the coil up or down, providing it is not perfectly level. The next operation will be that of truing the round and all work and bending of the spring for this operation is concentrated within the first quarter of the coil from its point of attachment and it is seldom ever necessary to make any bends beyond the first eighth of the coil from the attached point.

Figure 28 may be of some value in gaining an idea as to just how this inner coil should appear when it has been trued.

The broken lines ill.u.s.trate a condition after colleting and before truing. The heavy lines ill.u.s.trate two positions into either of which the coil may be formed in getting the spring true.

[Ill.u.s.tration: Fig. 28]

The outer black line shows the most adaptable form for most instances.

The inner black line shows the most practical form for use in instances where there is unusual s.p.a.ce between the collet and the inner coil. It will be noted that these two forms blend into the true spiral form of the spring at about one-eighth of the coil distant from the collet. These forms may be used as a basis for truing the spring in any instance in which it has been bent or mishandled around the collet after its original truing.

Experts always true springs after they have been staked to the balance and a light weight calipers tapered on one end to a smaller diameter than the collet is used for spinning the balance, making observations, and corrections.

Considerable progress can be made by some watchmakers in removing the spring from the balance and placing it on a colleting tool or tapered broach and then truing the flat and round as good as possible, after which it should be perfected in the calipers. When the balance is spinning in the calipers and the spring is true in the flat there will be no jumping or quivering of the coils as observation is made across the top of the inner four or five coils.

When it is perfectly true in the round and the balance is spinning in one direction the coils will seem to be whirling into a hole of which the collet is the center. When spinning the balance in the opposite direction the effect of the coils will be similar to the waves produced by dropping a small stone in still water and they will appear to be whirling away from the center. This effect in both instances is caused by the eye following the spiral form of the coils as the spring revolves.

83. _Treating a Rusty Hairspring._

When rust begins its attack upon any point of a hairspring there will be a constant loss in time until its advance is stopped.

Should considerable headway have been made by the rust before the watchmaker's attention is enlisted for an examination it may be necessary to change the spring entirely before good results can again be obtained.

There are many instances, however, in which proper care at the right time will produce as good results as will a new spring.

The first appearance of rust is generally indicated by one or more spots of a light brown shade and in such instances it has hardly attacked the metal to any serious extent, although usually enough to cause a slightly losing rate. At this stage the spots may be sc.r.a.ped with a piece of peg wood after which the spring can be placed in a small copper pan containing lard oil to a depth of about one-fourth inch.

This pan should then be held over an alcohol lamp until the oil becomes hot enough to smoke, after which the spring should be removed, immersed in benzine for about thirty seconds and then dried in sawdust. This treatment will stop further rust and the only indication of previous rust may be a removal of the color from the spot which had been affected.

In case that the rust has reached a stage far enough advanced to seriously pit the metal, good results cannot be expected from the spring even though further rusting may be prevented.

84. _Stopping by Escapement Locking When Hands are Set Backward, or When Watch Receives a Jar._

This is sometimes a very annoying trouble and while it should not occur on high grade watches at all, it does show up just often enough to cause a certain degree of unpleasantness for the owner of the watch as well as for the watchmaker.