Caliber 354 Accuracy Inquiry

Hello Fellow Omega Enthusiasts,

I just recently had a 1955 Certified Chronometre-grade 354 caliber movement overhauled by a repair shop and he spent a few extra days to get it adjusted to no worse than +10 seconds per day. I could have paid a good bit more to have him spend two weeks to get it a bit better, but I was more interested in having it back to everyday wear condition than having it adjusted to peak accuracy.

I am curious - does anyone have thoughts on what should be considered decent accuracy for a vintage movement? Obviously the bumpers are limited by their relatively arcane impact motion, but I feel as though +10 seconds per day for a 65 year old concoction of metal and springs is pretty impressive.

Also, I’m giving a shout-out to Zaf Basha at ClassicWatch.com, LLC in Washington, D.C. for timeliness, reasonable pricing, and absolutely stellar communication throughout the service.

I’m not sure about how to do a 6y positions test, but I wore it throughout the day for 7 days straight without adjusting the crown and compared it to my phone’s atomic clock signal time each day at 10 a.m. exactly and got the following results.

No more than +8 in any one 24 hour period, and because I live on a farm and workout throughout the day, I randomly take it off my wrist for varied periods throughout the day to avoid damage, put on an exercise watch, etc., so I imagine that had something to do with the varied results over different 24 hour periods.

I took the watch off around 2 p.m. on Wednesday and set it down for the count to check power reserve and noticed a slowing of the movement by the next morning (-13 seconds) and it was dead by this morning. I think that is probably to be expected in an older movement like this - in that the watch will start to slow the deeper into the power reserve it goes.

Watch Accuracy Notes - 10 a.m. phone time

• date of read: time on watch face • +/- difference between phone time (+/- difference over previous 24 hours)

• 05/20/20: 10:00:09 • +9 (day zero)
• 05/21/20: 10:00:14 • + 14 (+5)
• 05/22/20: 10:00:14 • +14 (+0)
• 05/23/20: 10:00:22 • + 22 (+8)
• 05/24/20: 10:00:21 • + 21 (-1)
• 05/24/20: 10:00:28 • + 28 (+7)
• 05/25/20: 10:00:28 • + 28 (+0)
• 05/26/20: 10:00:32 • + 32 (+4)

Power Reserve test (took off at 2 p.m. 05/26/20)

• 05/27/20: 10:00:19 • + 19 (-13)
• 05/28/20: stopped