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Watches Fail to Rate Properly

From Horology magazine, May, 1938

Watches Fail to Rate Properly
Editor Horology
Dear Sir:

As a subscriber to Horology I have a question I would appreciate if you could solve for me.
I am having trouble at times with high grade watches of the best American makes, 21-23 jewel grades, trying to make them run accurately. They seem to gain one day and lose the next.

These watches are not magnetized, the pivots are in perfect condition, the balance wheel properly poised and escapements match correctly. Sometimes these watches will show a variation of 30 seconds to 1 minute in 24 hours either way, and again they will run with no variation in 24 hours. At other times they run with a variation of only a few seconds.   I have had 15 years experience with watches and have been through a horological school.

On one occasion I sent one of these watches to the factory where it was made and had to send it back a second time before the trouble was overcome.

I would appreciate it if you could tell me what the process would be to overcome this kind of trouble.
R. T. C.

Answer: It is difficult to understand why watches of the grade you mention should have a daily variation of from 30 seconds to a minute. Such an amount is unreasonable, whether the watches vary this much from day to day while in the same position or whether they vary this amount from one position to another. 

The Bureau of Standards, in the Railroad Precision Test, allows a maximum difference of 12 seconds in daily rate between any 2 positions, although no tolerance is specified for a watch kept continuously in one position and temperature.

No matter how closely a watch may run under uniformly controlled conditions it will show some variation when kept in an ordinary room whose temperature is not constant.

However, in the case under consideration it would seem reasonable to assume that the watches are not in good enough mechanical order. If the variations in rate occur while the watch is in the same position, the trouble is very likely to be found in the transmission of power and not in the escapement. A poor mainspring, tight barrel arbor or center wheel are just a few of the defects which may contribute to an irregular rate. On the other hand, if you are troubled with position variations, the difficulty will probably be traced to the balance and hairspring.

You specifically mention that the pivots are in perfect condition, but the accuracy of this statement depends on the means of examination used. Mere observance with an ordinary loupe, of course, is not to be considered a test. Balance pivots cannot be adjudged straight or round unless tested in a true balloon chuck or in a Dorrington pivot polisher or similar tool.

It would be impossible to enumerate here all the possible faults which may cause a watch to take a variable rate.

For further enlightenment on the subject we refer you to "Practical Course in Adjusting" by Theo. Gribi, "Rules and Practice for Adjusting Watches" by Kleinlein and the section on adjusting in "Practical Benchwork for Horologists." 


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