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Twisted Stem?

tpt

By tpt
in Watch Repairs Help & Advice

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tpt Watch Enthusiast

tpt

Posted
Posted

Hello folks,

Starting out on my BHI 'technician grade' distance course here and I've got hold of 2 practice pieces. A quartz Seiko and a mechanical 'Chronostar' which has an automatic movement cal. 2788 which I'm presuming is ETA although I've yet to learn where to look for that gem of information...

Apologies if I get terminology a bit wrong to start with but I have a quick question...

The squared section of the winding stem has a slight twist in it. (counter clockwise. oddly)  would it be manufactured like this? or do I need to look at replacing? 

Many Thanks

 

Tim

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rogart63 Distinguished Member

rogart63

Posted
Posted (edited)

Many thanks. 

I wish I had a camera that could take a macro pic for you. 

Do you have a loupe ? Put it in front of the mobilecamera . Or any other camera that has a small enough lens . 

Edited by rogart63
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tpt Watch Enthusiast

tpt

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Do you have a loupe ? Put it in front of the mobilecamera . Or any other camera that has a small enough lens . 

brilliant. here goes...

post-661-0-63760200-1425483921_thumb.jpg

post-661-0-34102800-1425483416_thumb.jpg

Edited by tpt
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Geo Distinguished Member

Geo

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Now that's interesting.

Never having seen one, can someone please tell me why it is designed with a twist ?

Is it for operating a quick set system?

Edited by Geo
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Geo Distinguished Member

Geo

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That stem is shot .Takes a lot of force to twist like that . Nice picture with the loupe :)

I'm not convinced Rogart, I think it is meant to be like that. The twist is anti-clockwise, you couldn't cause that damage in the watch because the clutch would free wheel.

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Vich Distinguished Member

Vich

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Odd stem but apparently manufactured that way.  There is a bit on the net about it but finding out why it is made like that is harder to establish.  I did find this patent that seems to give an answer, whether its the right one I can't be sure but it certainly sounds like a good explanation.

 

US2655784.pdf

 

Cheers,

 

Vic

 

 

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tpt Watch Enthusiast

tpt

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For my first watch uncasing I'm happy to have generated such interest!

 

While we're on the subject of twisted things... who'd like to tell me if they think this can be saved??

From Junghans cal. J30 BZ aircraft clock.

Mark? 

 

post-661-0-57100400-1425494776_thumb.jpg

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bobm12 Distinguished Member

bobm12

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If at all possible I wonder about the time and trouble it would take...on the other hand, maybe it can be sourced (the hairspring alone) to be refitted? Let's hear the experts' opinions...

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Geo Distinguished Member

Geo

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I did find this patent that seems to give an answer, whether its the right one I can't be sure but it certainly sounds like a good explanation.

Great find Vic. :)

I'm absolutely sure you have found the right answer. It takes a bit of digesting, it would be a lot easier to see it in the metal.

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