This page details an experience of repairing a Swiss Sellita SW210-01 mechanical hand-wound watch movement. I chose this movement because it had a broken screw (minute train bridge screw). In order to remove it, I would need to disassemble the entire movement, which presented the opportunity to create a content series on taking the movement apart, extracting the screw, and reassembling the movement. I will be filling in the sections as I record and write the content.

Disassembly (coming soon)

Screw Extraction

The best way to understand how you can extract a broken screw from a movement is to watch the video [https://youtu.be/KynGevssTjk].

I used a Bergeon 30209 with extractors (broaches) sized 0.8mm on the side with the broken head and 0.6mm on the backside so it would go into the hole and grip the screw without damaging the threads. (NOTE: I say 0.4mm in the video, but it was in fact 0.6mm.)

You tighten the tips so that they grip both ends of the screw and then turn the plate. You should turn the plate in the direction that will remove the screw from the top of the plate as you would normally remove the screw. (NOTE: In the video I use the terms plate and bridge somewhat interchangeably as this is the main plate/bridge and the specific screw broken is the minute train bridge screw.)

Before & After

The damage around the hole already existed and was not caused by the Bergeon tool. I will clean it up a little and when assembled the scratches will be hidden by the minute train bridge.

Resassembly (coming soon)