I have three questions about Hamilton 992B watch movements:
1. Was the 992B ever sold with a dust ring?
2. Is there any safety feature in the movement to protect against train and escapement damage in the event of a broken mainspring (or is complete reliance placed on the unbreakability of the Dynavar mainspring)?
3. Does anyone know of a simple method for assembling the cap jewel onto the balance cock?

John Scott

hi john,

i will start..

no, these movements never had provision for a dust ring....

I have to yield to the watchmakers to answer your other questions....

Terry

Thank you. I am guessing that as 992B movements were always sold cased (true?) a dust ring may not have been seen as a necessity. I am not sure that this is an indication of a general rule about dust rings, however. John

it appears the watches for the canadian market may have been shipped in movement holders for casing in canada, so not 'all' movements were necessarially cased at shipment...

John,

Welcome to our discussion group and more specifically the 992B SECTION.

THE EASIEST WAY FOR ME TO ATTACH THE CAP ON THE BALANCE BRIDGE IS TO REMOVE THE CAP FROM THE REGULATOR POINTER AND CLAMP THE BRIDGE ON THE EDGE (SIDE) IN A SMALL HOLDER THAT WILL HOLD IT STEADY. NOW YOU HAVE THE BRIDGE SO YOU MAY GET TO THE TOP AND BOTTOM FROM EACH SIDE.
I START THE SCREW FROM THE BACK AND HOLD THE CAP ON THE SCREW UNTIL THE THREADS START. ONCE YOU HAVE ONE STARTED YOU CAN SNUG IT UP ENOUGH TO LINE THE OTHER HOLE UP .

I HAVE NOT RUN ACROSS ANY DAMAGED GEAR TRAINS DUE TO MS BREAKAGE.

Terry

That is most interesting, thank you.

I read the movement number as C161768 and the Grade number as C90, although both are a little indistinct for me. It would beinteresting to know some more about that grade number.

Jim

That sounds reasonable and I will give it a try, next time, thank you.

It is messy having to apply long screws from one side to a cap on the other. I have been leaving the index off and snapping it on later, as you recommend. I believe that this is a weak area in the movement design although I can see the virtue of putting the tapped threads in the cap instead of the balance cock. I appreciate having the benefit of your views.