Maintenance of caliber AS 1674
In the pictures below you can see the original state of the Onsa automatic watch, with a nice golden case.
You'll see the different steps in disassembly and cleaning, and how I removed a broken screw from the barrel arbor.
The screw head of the barrel arbor screw had broken off. It was removed by putting the barrel arbor in a lathe chuck, turning the lathe slowly clockwise, while grabbing the screw with a graver.