American PW case Removing Hamilton 992B Movement from Bar over Case


NAWCC Member
Jun 14, 2009
I started the thread on “Hamilton 992B Randomly Stops” and was pointed in a solution direction.

As I have never taken a 992B movement apart to clean I need to ask just a couple of questions to get me started.

First question, involves getting the movement out of the case with the bar over the winding stem. Normally on the few movements I have cleaned (11 of them), I would let the mainspring down, pull the stem up, case screws out, and then remove the movement from the bottom tipping it so as to slide it off the stem. It would seem I might need to take the bow and bar off to pull the stem up, but that would not make sense. I see a screw, the red arrow, on the movement picture. According to parts blow up it is the setting lever screw. I recall loosening about ¾ turn on a Studebaker watch a similar screw in order to get it out of its case. But in that case I still pulled the stem up.

Is that what I need to do on this case, loosen that screw and the movement movement will tip out will tip out without pulling the stem up?

Second question, this watch was recently serviced it is clean and I can see the bubbles in the cap jewels. As I just need to get to the mainspring barrel to look for binding issues I am planning to remove the barrel plate and not the balance etc first.
Is this a bad idea?

Should I just disassemble as normal?

How would a watchmaker normally repair just a broken mainspring?

Thanks in advance for the assistance.


992B Movement em1.jpg

John Runciman

NAWCC Fellow
NAWCC Member
Aug 13, 2003
Seattle, WA
the reason I'm giving you the link for the book below is pages 84 through 103 is basically the service manual for the Hamilton 992B. then the rest the book just has a lot of good information and servicing watches.

Them attaching two more PDFs on the Hamilton 992B. notice is a reference that the blue screw doesn't have to be loosened to remove the movement from the case.

you should build take the two case screws out leave the crown where it is obviously not to point out that the bar in place anyway. Gently push the movement out opposite of the crown him might have to turn the crown a little bit just to get at the come free. that's also explained in the PDF that I attached no need to loosen the screw

one of the things to do is to remove the balance with bridge to give you a better view of inside the watch. You can also take the pallet fork out and wind the watch and see how the train spins before you take the plate off to see the mainspring barrel. But if you want to just take the barrel bridge off that's fine too.

at the link below you want to download this book in addition to anything else it looks interesting while you're on the site 1945 TM9-1575 War Department Technical Manual.

Vintage Bulova Catalogs |


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NAWCC Member
Jun 14, 2009

Thank you for the links, I read them over and the help answer the questions. It looks like TD 127 implies the barrel bridge can be removed without affecting the winding system ie it will not fall out.

I downloaded the TM manual as well as the Joseph school.


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