Trench watch, availability of parts?

clockoclock · 2025-11-22T03:49:37-0600

I have this trench watch with a movement that I suspect is a Unitas. Correct me if I’m wrong.
Now, it seems it’s all intact but the problem is the balance wheel, the hairspring is kaput.

How should I approach this from a watchmakers perspective?
Find the correct replacement? I understand these were manufactured in their millions but that was more than 100 years ago so millions of them are also gone.
Just change the hairspring to a generic one?
Give up and call it a day?

Also, what do the markings on the case back and numbers on the edge of the back case tell the trained eye?
Some local watchmakers initials? Some more known?

Gratefully accepting information!

Canuck · 2025-11-22T14:38:33-0600

You might find many answers to your questions about stampings inside the case back in the link below. The case is Swiss. As to parts? I think you might be looking for a donor movement. To that end, you’ll need to confirm maker and calibre number. There may be a maker trade mark and calibre number somewhere near the rim of the balance wheel. Failing that, the dial and hands will need to come off so the setting parts can (hopefully) be identified in a “fingerprint” catalog.

https://www.vintagewatchstraps.com/swisshallmarks.php