I think the 0522 is the serial number, and the movement doesn’t have a calibre number. It’s just 10 1/2 ligne, and that’s that. You can see that the set lever spring is broken, and that the broken bit is left of the middle of the clutch lever.
The set lever spring with the broken off bit. I won’t be able to find a replacement, so I will put the spring back in as it is. The only effect will be that the crown doesn’t snap into its two positions, but you will still be able to wind and set the watch without any problems.
The mainspring is still straight and spritely, so I put it back into the barrel. This is one of the few jobs for which I wear latex gloves, as it’s hard to avoid touching the barrel when putting the spring back in. Basically, I never touch any parts after cleaning with my fingers, so it’s gloves if something needs to be touched.
Having cleaned the thread of the pendant tube and the crown, the crown now screws down without a problem. There were lots of fibres inside the crown, and the layer was so thick that the crown couldn’t even touch the first thread of the pendant tube.