Part 4 (1/2)

In placing limits of allowance for variation in various grades it is not intended that all watches of a particular grade will have the extreme variation. It is possible that an individual watch in the twenty-five seconds allowance cla.s.s may have an even better rate than another watch that is in the six seconds cla.s.s. It is also possible for a watch in either cla.s.s to have a perfect rate, although these would be rather exceptional instances.

24. _Some Necessary Requirements for Learning Adjusting._

The adjustments to isochronism and positions are not permanent to the same extent that the temperature adjustment is, and they can be damaged or destroyed entirely by the average workman in making ordinary repairs unless he is familiar with the common principles governing their production and maintenance.

Experienced workmen who are familiar with these principles avoid unconsciously doing any damage and make practical repairs in a manner that will maintain or improve the original adjustment and time-keeping qualities of the watch.

To know and to make use of these principles does not make a ”putterer”

of the workman, in fact the consequence is just the reverse, because the training acquired tends to eliminate guess work and enables him to determine more readily as to just what the trouble may be, how to correct it, and as to just what degree of perfection is required in a particular instance.

Certain practical requirements are necessary in reaching this standard of workmans.h.i.+p and it would not be profitable to attempt to do adjusting unless one has first had a reasonable degree of training as a watchmaker or repairer, especially in such branches of the work as truing and poising balances; truing, leveling and centering hairsprings; matching the escapement; finis.h.i.+ng pivots, and properly cleaning and a.s.sembling watches.

These mechanical requirements and experiences alone are not sufficient, however, and a certain amount of study must be consolidated with them in order to become proficient. This study should not deal so much with the problems of manufacture of the watch, or its various parts, as it does with the problems pertaining to the finished results that are to be obtained through refinement and intelligent a.s.sembly of these parts. The workman's willingness to indulge in such study is a very large a.s.set among the requirements, and it only remains for him to obtain the proper cla.s.s of instruction and then to conscientiously follow correct methods in his practice and to make personal experiments, conforming to the instruction, so that his confidence will become more enduring.

It is further required that he be capable of realizing the difference between genuine and imitation materials, especially such essentials as balance staffs, hole jewels, mainsprings and roller jewels, which are the most frequently changed and most frequently subst.i.tuted parts of watches. Imitation materials may be less expensive as a matter of first cost but staffs may have pivots and shoulders out of line, or out of true; hole jewels may be rough, out of round or extremely thick; mainsprings soft, or of improper proportion, and roller jewels may have sharp edges which cause rubbing in the fork and ”hanging up”

when the second hand is reversed. It is most satisfactory to depend upon the materials supplied by the manufacturer of the watch, as imitation goods are seldom any better.

25. _Train and Escapement Freedom._

Beyond a general insight of high cla.s.s watch-work this book is not intended to meet the requirements of beginners. It is designed princ.i.p.ally for watchmakers of some experience, and cannot presume to cover details that would be essential for those in early apprentices.h.i.+p. It is thought essential, however, to consider some matters in a general way and among these are the subjects of side shakes and end shakes, and the escapement, as far as they pertain to general inspection of the watch without consideration of details that refer to correction of irregularities which are presumed to have been acquired in earlier training.

Thoroughness of mechanical ability always demands a system of inspection and of making corrections and it is quite necessary to follow some method that will reveal any point or points that may not be up to standard.

As a rule it is best to begin at either end of the watch, and if it is to be taken down the best place to begin is usually with the balance and examine each part as it is removed until the barrel has been reached. If it is not to be taken down, just as good results will be obtained by beginning the examination at the barrel and finis.h.i.+ng with the balance. Sometimes watchmakers of considerable ability will demand as a basic consideration that pivots be fitted with very little side shake and that end shakes also be quite close if close time is to be expected.

These presumed to be, wide side shakes and long end shakes, very often have nothing whatever to do with the absence of a close position rate and frequently are absolutely necessary for good performance of the watch and proper s.p.a.ce for oil.

The importance of reasonable limits is of course granted, but it is very detrimental to have pivots too close fitting and more stoppage and irregular time keeping can be traced to lack of freedom than can be traced to excessive shakes.

If the repairer is not familiar with accepted standards of side and end shakes, he can improve his judgment by examining watches of the higher grades and comparing the results with those found in cheaper makes of watches.

Such examination will invariably disclose the fact that fine watches receive very careful consideration in this respect. The center, third and fourth wheels generally having from 0.03 mm. to 0.05 mm. freedom for end shake and 0.015 mm. to 0.02 mm. for side shake. The escape wheel, pallet and balance will be found to run quite uniform at from 0.02 mm. to 0.03 mm. freedom for end shake and from 0.0075 mm. to 0.0125 mm. for side shake. The smaller and thinner watches generally favoring the lesser figures and the larger and thicker watches favoring the higher.

This uniformity of freedom will be found absent in cheaper watches; for instance, a center wheel may have 0.02 mm. end shake and 0.01 mm.

side shake which would be very close fitting for large pivots. The fourth wheel may have as much as 0.08 mm. end shake and 0.03 mm. side shake which would be too great. The pallet may have 0.05 mm. end shake and the balance 0.01 mm. and in this instance the short end shake of the balance would be more detrimental in most instances than would the longer end shake of the pallet. The variation will even be found to exceed these figures and when they are found in connection with thick, straight hole jewels they often interfere with a close position rate and with regularity of time in service. The interference in timekeeping is considerably aggravated in cases where one pivot has excessive side shake and the opposite pivot is close fitting, as this tends to cause almost certain binding of the close fitting pivot as soon as the power of the mainspring is applied.

The end shake and side shake allowance for the barrel depends considerably upon its style of construction. Safety barrels constructed so that the arbor revolves with the main wheel, when the watch is running, may have about the same end shake and side shake as applied to the center, third and fourth wheels, and if the pivots of the arbor are quite large they may have a trifle more side shake.

As a rule larger pivots will stand more side shake than smaller pivots; this, however, does not apply in the case of large bearings, such as safety main wheels that revolve around a stationary arbor, or going barrels where the entire barrel revolves around the stationary arbor when the watch is running.

In such instances the main wheel or barrel should have from 0.03 mm.

to 0.05 mm. end shake on the arbor and should be just free for side shake.

The arbor which turns only when the watch is wound requires merely freedom for end shake between the plates, as well as for side shake where the pivots pa.s.s through the plates.