So I have a watch that when you set it and sit it on the dresser, it will be almost perfectly on time the next day. But when worn, it will gain minutes in a few hours....what causes that? And it’s a manual wind, not auto-wind
Have you tried setting it down in different positions to see if it speeds up? (Dial up, dial down, crown up, etc.)
That’s my next step. But such variations in speed depending on position- I get by a second or a few seconds, but minutes??
last time I had that happen it was a problem with the balance staff jewels. the watch likes one position but freaks out when tilted. edit: actually I can't remember if the staff was screwed up as well.
now that I think about it I seem to remember the staff was snapped and not fully engaging in both the top and bottom jewel. depending on position of the watch.
The delta or difference between wearing it and resting it seems to be too large to be within an acceptable range. Perhaps a watchmaker will come in and offer an opinion? For example, a 1966 Valjoux 72 based watch of mine that runs spot on day after day, positional differences are . . . Fully wound: Dial-up = +12 seconds a day Crown Down = +2 seconds a day. Crown Up = - 4 seconds a day 1/3 wound: Dial-up = + 6 seconds a day Crown Down = - 6 seconds a day Crown up = - 5 seconds a day When I wear it regularly it typically gains a few seconds a day, but after resting it crown up overnight, it's pretty close to being spot on in the morning. Is it possible your magnetic personality is causing it to speed up? Edit: A good suggestion was made while I was typing.
yes this is what leads me to suspect a jewel-staff problem as the time keeping is so radically variable depending on position.
The balance was removed for cleaning (not by my watchmaker, but watch buddy), it’s possible he didn’t seat it properly- and now it’s gained 15 minutes in 2 hours so perhaps we have a kinked hairsping.
would a kinked/sticky/out of shape hairspring be position-sensitive like you are describing? I guess Al would be able to answer that one as my guess would be no.
Very true- kinked hairsping s I have had before (recently we’re consistently fast- and just sorting t got them back on time without any other adjustment. The irregularity is puzzling- I’ll have him pull the whole balance and inspect the staff and seats.
In regard to your original question, it's possible that the hairspring has just enough magnetism that it needs a little push to "short out". When walking, it sticks and releases depending on your movement. Resting has no effect.
Good thread. I have a Zenith Sporto that has the same issue. And the movement sounds like a "trot" of a wild horse. Then disappears after a few minutes.
In another thread I mentioned an 1940’s Elgin I have that was running really fast (gaining 15 minutes a day or so) and thought is was magnetism. Turned out it was the hairsping hanging up- once that was straitened out, it ran within 10s/day without adjusting anything else- but that was a consistent gain. The fluctuations here is what’s curious. My watch buddy put it on a timegraph and it fluctuates wildly just turning it in different positions. He had it apart last night- will find out today what he found.
Could be a broken balance staff pivot as well but I stand by my first suggestion. Different accelerations cause the spring to stick or not.