I’ve seen a lot of people talk about how a co-axial Si14 watch *might* respond to magnetism so I thought I would share my experience with my Speedmaster 38. At my company, we have incredibly strong white board magnets (seriously much more strong than any casual magnet I’ve encountered anywhere else in life).

At 2:06pm I placed a phone call while I was working near these magnets. While getting ready to leave the office around 5:00 I was caught by a coworker who felt it was a perfect time to chat at my desk. When I glanced at my watch to give the hint that I was trying to leave I noticed the movement had entirely stopped. After a moment of confusion and panic, I remember the magnets and cross referenced my phone calls. The watch had stopped at exactly 2:06.

Now fearful that I caused damage, I rewound the watch (~15 turns of the crown) and it began running again. I reset the time and so far I have not seen any inaccuracy in the time keeping.

It appears that this movement doesn’t lose much (if any) accuracy by being magnetized, but strong magnets will halt the movement.

Of course your results may vary, but from what I’ve seen I’m impressed.