When this watch arrived, nothing was broken, but it was not running, The escapement was in “over-banked” state. This is a mechanical state where the roller jewel on the balance wheel has gotten outside the pallet fork. The balance wheel can then only turn to one side and not the other because the roller jewel just hits the outside of the fork on one side rather than passing into it (and then moving the fork, and releasing the escape wheel). The mechanism has a guard pin on the pallet that normally gets in the way of the roller getting out of sync in this way. But if things are out of adjustment, that doesn’t work and a jolt at the right moment will jog the balance out of rhythm and get it to over-bank.
As a last step on this watch I expected to have to adjust the banking pins and guard pin (and hopefully nothing else) to make sure over-banking is blocked. However, it all checks out as is. The pallet can not pass by the balance out of sync.
It is possible to over-bank a watch with just the right jolt at the right instant, even when things are all correct. But such a jolt typically has to be enough to actually break something. It seems this watch got lucky.
The winding/setting mechanism, or "keyless works", on early Elgin ladies movements is problematic to say the least. There's a spring pushing one way on the topside of the base plate and one underneath pushing the other way. They both have to be in good condition for winding/setting to work.
Both these springs however are prone to breaking, or just wearing out. Old steel formulations lose their tension over decades.
I always dread working to get one of these to function properly, but this one was no trouble at all.
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