All,
I am thinking about purchasing a used watch with the calibre 1120 movement. I believe the tolerances for this movement new would be about + or - 3 seconds per day. Should a used watch perform to that standard to be considered to be "keeping time" accurately, or am I being picky there? Any thoughts and inputs are appreciated.

Thanks,

Clay

 

COSC chronometer certification is +6/-4 seconds per day- that's for a new out of the box watch. I think your expectations are high. I see you post count is low. You will see a lot of threads on here talking about exceptional timekeeping performance of mechanical watches - most of it is bunk, or the owners have that one in a hundred example that keeps really good time. I would say set your expectation at +/- 10-15 seconds/day. Otherwise get a newer watch with a COSC or higher certification. Just my 2 cents.

 

Omega specs for this movement, and all their COSC rated watches, is that the average daily rate should be between -1 and +6 seconds per day. So Omega specs for average rate are tighter than COSC.

I would expect any modern watch with this movement that it in good condition to meet these specs, and if it doesn't, then I would suggest paying a price that would allow having a good watchmaker look it over.

Ideally you would want to know when the last service was, and who did the service. If the seller can't provide proof of a recent service by a known good service provider, then I would budget for a service in the near future. If it turns out you don't need to do that service, consider it a bonus.

Cheers, Al

 

My new Seamaster is losing a few seconds a day but my understanding is that this may change after approx 6 weeks? Not a concern and still incredibly accurate for a mechanical automatic (although I see most gain time.)

 

Do you leave it in the same position at night? If so try a different one.

 

When I take mine off I leave dial up, what would you recommend? Not that losing a few secs a day is a problem, just interested!

 

Watches keep slightly different time depending on the position of the watch due to gravity effects on the hair spring. Try it on its side at night it might keep perfect time.