The two models look very similar and the main difference is the movement inside. The Thincraft I used the 22 jewel 770 movement with a sub second hand while the Thincraft II used the 18 jewel 735 movement with a sweep second hand. Both models came with white or silver dials and white or yellow gold filled cases.
I think it's interesting that the Thincraft II had a different dial pattern for the white and black dials but the Thincraft I has the same pattern for each color dial.
Both models have very long delicate lugs and I wouldn't be surprised if a lot of Thincraft examples have been lost to time by having a lug or two break off.
I recently had a fellow collector send me his newly acquired Thincraft I example and it was a real beauty.
I don't know how much wrist time this watch has seen in the last 60 years but it couldn't have been too much. The case back looks similar to a Thincraft II but it's a little flatter since the 770 movement doesn't require much depth.
The inside of the case back has a recess to securely hold the 12/0 sized movement.
This movement is very clean looking but that doesn't mean the oil inside hasn't evaporated and gummed up. So even a clean looking movement should be overhauled every few years.
This watch even has an original Hamilton custom deluxe strap...
... and Hamilton buckle.
Everything is cleaned and ready for reassembly.
Once the balance jewels are secured under their shock spring the balance has a smooth motion. This is looking good so far.
Well, there's not much to complain about this 60 year old Hamilton movement.
I can't say the watch looks too much better than what I started with but I can say that it's now ready for some worry-free wrist time.