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Erratic Timegrapher Trace for Rate


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It turned out to be the hairspring not correctly centred and the coils would touch at high amplitude, causing a rate rise. I adjusted the hairspring to make it more concentric (as much as a coil can be) and retested the watch.

The rate was stable, even when making adjustments, whereas before, an adjustment to the rate or beat would upset the balance and make it unstable. The fault was hidden from my initial reading before strip down because the watch couldn't attain a high enough amplitude, the clue was the high beat error. When I initially lowered the beat error, unknown to me, I was overcompensating for the HS problem and when this was corrected the beat error came back at the same amount, but in the opposite direction.

I've added a final timegrapher trace and a pic of the finished watch. It is stable in amplitude and rate to within a couple of seconds in all positions.

Thank you all for your help and assistance, I have now learned a few more things.

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13 hours ago, ClusterFoxtrot said:

It turned out to be the hairspring not correctly centred and the coils would touch at high amplitude, causing a rate rise.

Very good, congrats! I'm also happy to have, for once, got it right on my 1st post here.

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