Demagnitizing

Recently, I sent a watch away for full service and when it came back months later, I was unhappy with what I was seeing on the Weishi timegrapher, with a beat error between 8.0 and 9.5 msecs and with an amplitude of 260 under the best of circumstances, fully wound and dial-up.

The first thing the watchmaker suggested is that a Weishi is not a Witschi and of course, that I already knew. I have had very good results with the Weishi evaluating other watches serviced by another watchmaker and I believe it to be reasonably reliable.

The watch under discussion is an easy to adjust EP40-68 movement based watch.

The watchmaker next suggested that perhaps the watch was magnetized in shipping. This did not seem right to me, because the watch was not running fast. It was running very slightly slow, maybe - 6 seconds a day +/-

I am hoping that Archer or another watchmaker sees this posts and makes a helpful comment or two.

My understanding is that generally, when a watch becomes magnetized, this has the effect of shortening the mainspring (as it sticks to itself) and the watch can speed up dramatically.

I am a lay person so who am I to argue? I bought one of those $7 Chinese blue degausser/demagnetizers and after giving it the treatment. No change.

Needless to say the watch is now back with the watchmaker and I am waiting for a report and remediation.

I have a lovely Gallet MC45M "Snow White" and what possessed me to try the degausser on it . . . is natural curiosity, I would suppose. The MC45M was running perfectly with amplitude from 250 to 340 and with a beat error that ranged from 0.3 to 0.6.

After running it through the degaussing process, naturally the watch had to be readjusted. I got the beat error down to between 0.1 and 0.3, but I never saw an amplitude above 275 again.

In future, unless someone more knowledgeable convinces me otherwise, I will not subject another mechanical watch to a demagnetizer unless it has suddenly increased its beat rate.

Comments welcome.

Cheers,

Joe

Fast running can be linked to hairspring coil stick together by oil.
Did you open the watch to check hairspring ?

I had a ‘70’s cardinal jumphour that got magnetized somehow. It started gaining +/- 15min per hour. Demagnetizing at the watchmaker fixed the problem.

Interestingly, it took me an hour and +/- 15 minutes to get from my house to the watchmaker, but only an hour to get home

What I observed in 4-5 watchmakers I have visited here in my hometown, is that they all have a cheap Chinese demagnetiser on their desks... I asked all of them if this works and they all replied: "it does not harm the watch so I try it before I start adjusting precision..". All these watchmakers are independent locals, so don't take this post as an indication of what should be done...

I am totally with you here!
I bought a cheap blue chinese demagnetizer last year, as i suspected my 2254 was running fast all of a sudden. Then i did exactly as people advice.. Once i held the watch close to demagnetizer, i heared a really loud noise and felt massive vibration in my hand. Probably was the balance still oscilating. I got so scared to do more damage than any good, that i never touched that thing again! Not sure if one has to hack the movement prior to demagnetizing or not.