Waltham P.S. Bartlett

This is a Waltham 18 size, 15 jewels, P.S. Bartlett model. Key wind and key set.

One of the banking pin screws was broken. Again, I was able to find one (exactly one!). This is lucky. These parts are only found on the earliest Waltham 18 size movements. They are unusual for banking pins in that there is a wide head, rather than having threads that go all the way out to the top. On other watches, like a comparable Elgin for example, a variety of banking pins would work and look fine. On this movement, it has to be this one.

This movement key winds from the back. Here are some images of the mainspring ratchet on the dial side.

I think I have replaced one regulator pin on every one of these I have serviced. I have no idea why it would be so frequently missing.

This view slows the regulator, in place.

Replacing the roller jewel on one of these is a specially challenging due to the hairspring being directly above, on the same side. So I didn't take any photos of the process... It's ticking now though.