That's one dirty mainspring...
A replacement balance staff and one balance jewel and it's running nicely. The keyless works on these often functions poorly just due to design flaws and aged steel spring, but this movement is acting like it will be fine in that area.
The big problem with this watch was that the winding arbor end of the stem was completely sheared off. The piece fell out as soon as I removed the movement. That's an odd thing to find broken like that, but later I found out why. The first thing to do was to figure out how to get the crown off without the stem to grip.
This required removing the latch spring from the case body, something I almost never do, so I proceeded with caution. On this case the spring is held with a retaining pin. I was able to push the pin all the way in and out of the way. Then the spring could be removed, and I could reuse the same pin when I put it back.
This required removing the latch spring from the case body, something I almost never do, so I proceeded with caution. On this case the spring is held with a retaining pin. I was able to push the pin all the way in and out of the way. Then the spring could be removed, and I could reuse the same pin when I put it back.
This design is called "negative setting". You can see how the stem pops over a shoulder in the stem. You can also see the larger hub on the stem that pushes the case's latch spring down to open the front.
This is the stem I found to replace the broken one. It's a very good match (these parts are not standardized).
Reassembled, this case looked like everything would work, however it was really hard to get the movement in the case, and the stem bound badly when in winding position. Looking at the neck of the case I realized why. And I now see why the stem was broken. It's bent. How this could happen without other damage to the case is beyond me.The crystal was broken of course, but that's it.
The case ended up having to be replaced, but it's finally ready for a few days of testing. This is the last watch from 2021.
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