Lightly wound watches running really fast!
So I tend to wear a number of watches on rotation rarely wearing a watch for more than a day or two.
Usually when I pick up and set an automatic watch I will just give it a few winds and then rely on the watch further winding up as I wear it.
It has been very noticeable with several watches that they run really really fast in that early period while being further wound on the wrist. Now I am talking in the region of +5 minutes in the first hour! It’s noticeable as I then have to reset the watch not long after having first set it.
If I am organized I will sometimes put the watch I plan to wear on a winder for a while before setting it but it’s not often that I am organized or decisive enough to have planned that far ahead.
Having noticed the trend, I was curious as it seemed counterintuitive to what I expected. I thought the watch being lightly wound would run slower than the fully wound turbo.
But courtesy of the big Swiss R’s information “as the mainspring power reduces so does the amplitude and therefore the watch runs faster”. Now I don’t own any Swiss Rs but I assume that the same applies to my far humbler watches.
Yet another learning day from this fine hobby.
Driven to watches (researching and collecting affordably) by the boredom of COVID lockdowns. My - possibly attainable - grail watch would be a 6245 (Seiko or Grand Seiko) in nice condition … someday.
When there’s less power in the mainspring as is the case when the watch is only barely wound, the balance isn’t going full force, which can enable the watch to run fast. Watches run at their most accurate rate when the mainspring is fully wound. Most manufacturers recommend that you wind an automatic watch anywhere from 20 to 40 times before putting the watch on the wrist and allowing the rotor to take care of the rest throughout the day. 👍
Interesting. I recently was googling the correlation between amplitude (higher when the watch is more wound up) and rate, but couldn’t really find any good info on it. I guess my search terms were bad. Anyway it sort of makes sense because the balance wheel is not turning through as many degrees of rotation when the amplitude is lower, so it would seem to do that faster (it’s rotating less distance in both directions) and thus equate to more beats per minute and thus a higher rate. Strangely though, I do see some watches run faster at higher amplitude too. I guess the effects of isochronism are reduced at very low amplitude?
Interesting. I recently was googling the correlation between amplitude (higher when the watch is more wound up) and rate, but couldn’t really find any good info on it. I guess my search terms were bad. Anyway it sort of makes sense because the balance wheel is not turning through as many degrees of rotation when the amplitude is lower, so it would seem to do that faster (it’s rotating less distance in both directions) and thus equate to more beats per minute and thus a higher rate. Strangely though, I do see some watches run faster at higher amplitude too. I guess the effects of isochronism are reduced at very low amplitude?
Haven’t researched is heaps (yet) but my guess would be that there is a sweet spot where isochronism applies but at the extremes it does not. I suspect we see it at the unwound end but not at the “overwound” end because of a combination of the escapement pallet working more effectively at higher amplitudes than at lower amplitudes, and possibly also because manufacturers restrict overwinding (but that would be at the expense of power reserve so I’m not sure how much they would do that).
Haven’t researched is heaps (yet) but my guess would be that there is a sweet spot where isochronism applies but at the extremes it does not. I suspect we see it at the unwound end but not at the “overwound” end because of a combination of the escapement pallet working more effectively at higher amplitudes than at lower amplitudes, and possibly also because manufacturers restrict overwinding (but that would be at the expense of power reserve so I’m not sure how much they would do that).
That’s what I was thinking. Excellent summary