I recently purchased 950B for my own collection, dial perfect, case is very good and can always be changed later if I wish. The movement is in good condition so I decided to test myself and the watch a little and see how accurate I could make it, so stripped and service it polished pivots etc, poise static and dynamic the balance, tweaked everything I could see, of course this was my hobby piece and would do a little and set to one side having to keep up with the flow of customer work. So far looking great.
There are a good few things to do if I wished cosmetically, screws etc and I could try to correct the PU & PD error but think I may throw out the other readings and have spent enough time on it, so will leave that to the next person who works on it. Watches like these can sometime still run better than most wrist watches out there, suppose that is why they had to make quartz watches

So far I have for a 73 year old watch (1942)
FU 0 298
FD 0 310
PU +3 284
PR +1 287
PL -1 300
PD -4 288
I make the average to be 0.16 s/day

1

2

3

4

5

6

7

9

Great numbers, I agree for a vintage 1940's watch, and great testament to Hamiltons RR pride & joy line !! What is the serial number on your watch Chris ?

regards,
bb

Hi Buster,
S2673

Nice Chris..

[FYI ONLY] I would expect that if the case is original to the movement that it should have a K1310000 to K1360000 case up to perhaps a K030000 to K039000 numbered Keystone case.

SEE: KEYSTONE-HAMILTON CASE A, 11, 14 AND 17 DATABASE EXAMPLES YEAR-BY-YEAR

regards,
bb

mine is K096068 and the entry shows the movement to be 1942


1940 - 1210000

------- During 1940 they began using a "K-Prefix" -------

1941 - K1310000

1942 - K1360000

------- During 1943 numbering system changed to "K0" and shorter overall numbers -------

NOTE: Some cases numbered without the "K" prefix but beginning with "13" have been found, these are apparently part of this particular numbering transition period.

1943 - K030000

1944 - K039000

1945 - K041000

1946 - K090000

1947 - K170000

1948 - K200000

I think I saw something else very familiar on your bench, Chris.

Regards! Mark

mickey mouse watch?

That's the one!

Regards! Mark

I was just wondering how much harder it would be to time a watch in 1900 , like most things we have it pretty easy in some ways.

Chris,

The 950B's excellent rate holding performance is not surprising. From my own (past) experience, the same performance can be achieved with a well tuned 992B since both models share the same train and escapement geometry. The same can be said for military versions such as the 4992B. The M-23 is also up to the same performance capabilities. All 16 size models of this era share the same mono-metallic balance and Elinvar hairspring, which I believe is a key factor to their stunning timekeeping precision.

I think it's safe to say that no watch company in the world made watches that were functionally superior, in terms of ruggedness, reliability and accuracy, to the hi grade Hamiltons produced during the 40's and 50's. ...of which the 950B is the best. Certainly the best looking!

Your bench and work environment look very inviting. You're photography is great as well!

William