Persistent magnetisation

[skridlov]

I've been using one of the "blue box" demags with variable success.I have recently bought one of the "Bergeon" - style units. The box even has that name faintly on the image of the device. 10% of the price and surely off the same production line. However I'm encountering very variable results even when using the recommended technique - drawing the un-cased movement slowly away from the demagger. I have a Borgel movement that resolutely refuses to play - although when I first subjected it to the new box it seemed to work extremely well - even running a little slow for a while. Another watch with a tiny movement responded instantly. Every pass with the Borgel, changing the orientation each pass, shows the same deflection of a compass.

Any suggestions?

Roy

[Chopin]

I bought a demagnetizer specifically for a watch that had all the symptoms of a magnetized watch.

I demagnetized it and although sometimes it seemed like it didn't work, sometimes it did. It would run fine for a few hours, at most, and then go back to running way ahead.

I eventually inspected the hair spring and it was damaged. Might want to check it out.

[skridlov]

Thanks. Well, the hair spring looks ok if a bit eccentric. What puzzles me is that when placing it over a compass there's a significant deflection. But short of pulling the balance out (which I have no intention of given the age and complete unavailability of spares) it's hard to be certain.

On a broader note, I'm pretty horrified by the extent of tool magnetisation - my calipers practically dragged the compass off the bench. Oops...

Roy