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Gruen VeriThin Lift Angle?

dpn

By dpn
in Watch Repairs Help & Advice

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dpn WRT Addict

dpn

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Hi all,

I'm curious as to whether anyone knows what a common lift angle would be for Gruen VeriThin movements?

I've seen that 36° is typical for American pocket watches, but given that Gruen's movements were manufactured in Biel/Bienne I don't know whether it's reasonable to assume a 36° lift angle.

I've seen several posts on the NAWCC forum explaining how one actually measures/calculates a lift angle, but they're, frankly, beyond my ability to achive.

More generally, how important is it to get an *exact* lift angle when judging the accuracy of a movement on a timegrapher?

Thanks all for indulging this newbie question. I appreciate any insights this forum might have!

Cheers,

Dan

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jdm Distinguished Member

jdm

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15 minutes ago, dpn said:

More generally, how important is it to get an *exact* lift angle when judging the accuracy of a movement on a timegrapher?

Zero importance. As explained many times the entered lift angle only affects the amplitude reading, and nothing else, to the rate of few amplitude degrees for each of lift angle divergence.

Old, paper strip timegraphers did not calculate amplitude at all.

Edited by jdm
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dpn WRT Addict

dpn

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Thank you @jdm! That's a great explanation, and I feel a little foolish asking this question. I can see that the amplitude looks healthy with my eyes, and assuming a 52° lift angle my timegrapher is showing a 250° amplitude.

The movement I'm looking at is, however, running very slow (-3m/day) so I'm looking into giving the watch a CLA.

Cheers,

Dan

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JohnR725 Distinguished Member

JohnR725

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1 hour ago, dpn said:

I've seen that 36° is typical for American pocket watches, but given that Gruen's movements were manufactured in Biel/Bienne I don't know whether it's reasonable to assume a 36° lift angle.

I would be curious as to what a typical American pocket watch is? I think you'll find the video at the link below interesting it shows a nice simple method how to figure out the lift angle. Of the pocket watches that I've done 36° is a bit on the low side. On my list 38° is the lowest and I guess a six size is not a pocket watch because I have a couple of those that were 62°. I would say on average closer to 45° would be a better average for American pocket watches.

https://youtu.be/-Xgcck692js

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nickelsilver Distinguished Member

nickelsilver

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Gruens would have a 2 arm balance (with some exceptions maybe). From dead zero the balance arms will switch places at 90 degrees when the are above the pallet fork. 180 degrees is when the look like they are hitting their rest position. Wind the watch until they are there, it's easy to see, then set your machine so it reads 180 degrees. Now wind up fully and you know where you are.

With 3 arm balances it's worth making magic marker marks at 90 degrees each side of the pallet center. Remove them after with pegwood and alcohol (works for permanent marker too).

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dpn WRT Addict

dpn

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On 7/18/2020 at 1:46 PM, JohnR725 said:

I would be curious as to what a typical American pocket watch is?

I saw that 36° figure cited somewhere -- maybe the NAWCC forum? But I have no idea whether that was someone's spitball guess or whether its based on hard data.

Thanks @JohnR725 and @nickelsilver for the info on how to measure the lift angle. For me and this specific watch, this exercise is beyond me. I am thinking about trying this calculation out on one of the NH36 movements I have sitting around, though.

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