New Staff/New Adjustments?

[tymekeypur]

Hello ~ am relatively new to watches and am considering the purchase of a Hamilton 992B...now, in examining the watch I noticed that among the watchmaker marks on the cuvette is a date and the word "staff"...now I'm assuming that the balance staff was likely replaced on that date and if so, does that mean necessarily that the advertised 6 position adjustment that came with the original movement is likely not applicable now?...thanks!

jc #157194

[tymekeypur]

Hello ~ am relatively new to watches and am considering the purchase of a Hamilton 992B...now, in examining the watch I noticed that among the watchmaker marks on the cuvette is a date and the word "staff"...now I'm assuming that the balance staff was likely replaced on that date and if so, does that mean necessarily that the advertised 6 position adjustment that came with the original movement is likely not applicable now?...thanks!

jc #157194

[GandalfPC]

If the replacement was done correctly then it should be just as good as the original.

Jason Goldman
Apprentice Watchmaker

[Don Dahlberg]

Even without the replacement of the staff, the 6 position specification may well be gone. Replacing the staff requires that the balance be repoised. Over time, the watch went through many cleanings which means the hairspring goes out of round with all the handling. The hairspring needs to be kept true in the flat and in the round. Properly poising a balance and hairspring takes time, which means money. If you are not practiced at it, it takes a great deal of time. That is why railroad watches were so expensive. Few watchmakers outside of railroad inspectors worry about doing a really good job of poising and adjusting.

Here are the Hamilton 992B specifications from 1943 and 1958

Compensation:
8 seconds maximum variation between 95 degrees and 40 degrees
24 hours in each temperature
dial up position

Positions:
24 hours run for each position before casing.
6 seconds maximum variation between dial up and dial down.
10 seconds maximum variation between dial up, dial down, 12 up.
15 seconds maximum variation between dial up, dial down, 12 up, 3 up, 9 up.
20 seconds maximum variation between dial up, dial down, 12 up, 3 up, 9 up, 6 up.

Timing limits after movement is cased:
Test rate for five days in pendant up position
Maximum mean variation during consecutive number of days, 5 seconds
Regulate to time from 0 to +5 seconds
Regulator to be moved maximum of one-half division either side of center.

If you can keep the temperature constant, you can check it out and see if it still meets these standards.

Don Dahlberg

[GandalfPC]

Don is certainly correct - the watch may not be adjusted to positions if it hasn't been carefully serviced - but a proper servicing will be able to put it back into shape.

A watch that is made to 3 positions will most likely never be able to be adjusted to 6 positions. This is because the design of the watch is incapable of it.

A watch that is designed to 6 positions such as the 992b may not currently be fully adjusted, but the design of the watch is capable of it - so as long as the staff replacement was done correctly it will be able to be adjusted by a professional to meet it's original specs.

Even if the staff was poorly done parts for the 992b are fairly easy to come by so it could still be repaired to meet the original factory specs....

Jason Goldman
Apprentice Watchmaker

[tymekeypur]

Thanks gentlemen!...appreciate your advice...btw:
I BOUGHT the watch!!!OH jooooooyyyyyyyyy!!!!!!

jc #157194

[Steve Maddox]

For what it's worth, Hamilton 992-B models (as well as Model 23 chronographs, 4992-B models, 3992-B models, etc.) have friction-fit balance staffs, which usually do not disturb the poise of the balance wheel upon being replaced.

I have no idea who invented the friction-fit balance staff, but it was a great idea that for some reason, was rather slow to catch on. I've worked on old Adolph Lange watches from the late 1800s that had them, but I'm not sure if those were the first.

Among quality American watches, the earliest company I know of that used friction-fit staffs was Waltham. The 16s 1899 models have them, as do the 12 size models of about the same era (1894 models?). In any event, after Waltham proved them to be successful, the E. Howard Watch Co. began using them, then Hamilton introduced them with the "Elinvar" models, and finally Elgin switched to them with the 571 series, etc.

The last three American watch companies to produce railroad grade pocket watches were Waltham, Elgin, and Hamilton, and by the late 1940s, all three were using friction-fit staffs exclusively in all their remaining pocket models. Along with the temperature compensating hairspring, the Invar balance wheel, and the white alloy mainspring, the friction-fit balance staff was probably one of the last significant improvements ever made to conventional mechanical pocket watches. Of course, among wristwatches, shock resisting devices were a great improvement, but for some reason, those never became very popular among pocket watches.

In any event, if a watchmaker is reasonably skillful at his craft, there's no reason to disturb the positional adjustments of a watch just by replacing a friction-fit balance staff.

------------------

Steve Maddox
President, NAWCC Chapter #62
North Little Rock, Arkansas

[tymekeypur]

Thanks Steve ~ have come to have the highest regard for your skill and advice...my goal (since I've gotten into watches ~ was/am a collector/repairman of clocks) was to: 1) fix my Dad's 'Mido Multifort' (which I have done, having repaired the setting mechanism) and 2) to clean and adjust my own Rolex Oyster Perpetual (which runs consistently slow and from which I am at least a year+ away from even opening the back)...if'n I don't get to that skill level I will be asking you to have a look-see sometime in the future...thanks!...Jim

jc #157194