It is inevitable that parts will wear out. Tolerances will no longer be what they used to be as pivots, jewels and bushings wear down. It also might be that old “gunk” keeps the components supported. Washing them off after a service, while good for longevity of the movement, might introduce freeplay that would otherwise impact isochronism. Usually fresh parts, replacement of jewels, bushings, checking of end shakes/axial shakes, re-poise of balance etc should improve isochronism and hence timekeeping performance. I wouldn’t sweat about it. +8-9 isn’t half bad. It’s a mechanical device and give it a break.
I watched you in the video, but I didn’t see you put any break-in grease for the spring.
What can be done to get it to COSC timing again? I had mine serviced and before the service it was running +1-2 per day, now it's running +8-9
It is inevitable that parts will wear out. Tolerances will no longer be what they used to be as pivots, jewels and bushings wear down.
It also might be that old “gunk” keeps the components supported. Washing them off after a service, while good for longevity of the movement, might introduce freeplay that would otherwise impact isochronism.
Usually fresh parts, replacement of jewels, bushings, checking of end shakes/axial shakes, re-poise of balance etc should improve isochronism and hence timekeeping performance.
I wouldn’t sweat about it. +8-9 isn’t half bad. It’s a mechanical device and give it a break.
I need my watch (same model) serviced but I'd rather not have it polished. Nice to watch the work done.. 👍🏻