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Proper amplitude for Unitas 6497

beastomaniac

By beastomaniac
in Watch Repairs Help & Advice

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Marc Distinguished Member

Marc

Posted
Posted

Nothing like getting some actual data so I have just put my own 6497's on the timegrapher.

I have a 1960's Le Cheminant pocket watch with an original 17 jewel UT6497 running at 18000bph which I have just serviced (last weekend). Still using original Ms and with the lift angle set at 44° I am getting 271° amp on full wind in the horizontal.

I also have a modern De Tomaso wrist watch with an Asian 6497 clone running at 21600bph. It's about 3 years old and I haven't serviced it. With the lift angle set at 44° I am getting 290° at full wind in the horizontal.

I would say that 240° at full wind was a little low for a freshly oiled modern movement.

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szbalogh Super WRT Addict

szbalogh

Posted
Posted

Yes, like jdm said. If the rate is the same or within 5-10 sec/day difference in the different positions then its ok. Many thing can couse low amplitude. I suggest to check amplitude again after a few days. All the watches i serviced had different gain in amplitude after a few days.

Maybe i make something wrong :) 

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JohnR725 Distinguished Member

JohnR725

Posted
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I assume you meant 6497-2 which runs at 21,600? So because I wasn't 100% sure I've attached the specifications for both the 18,000 version and the 21,6000 version timing specifications amplitude etc. You notice they only give a maximum amplitude not a typical running amplitude. The only way to really tell if what you have is right is to wait 24 hours and it has to be better than the minimum.

Then in real life you don't care what the amplitude is sort of. Normally people are more concerned about timekeeping not amplitude unless they're having a problem with timekeeping. What you want to look at is the isochronism number variation from fully wound until 24 hours later. If you're getting that who cares what the amplitude is?

6497-1.JPG

6497-2.JPG

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