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Help with AS984 balance wheel shaft please

Deggsie
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Deggsie WRT Addict

Deggsie

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Hello. I'm new to repairing watching and still learning little by little thanks to the help I'm getting from here. I recently bought an old rotary sold as spares/repairs and wonder if you could give me some help please. I have diagnosed the problem (or at least one I can see so far) as being that the balance wheel will not rotate without clashing on surrounding metalwork. The balance wheel has a lot of movement both axially and radially, and, to my mind seems to be sitting far too low in the jewel hence the underside clashing on the adjacent metal work. Now, I have carefully removed the balance wheel/ hair spring/ cock assembly and I note the following which I hope you may be able to comment on:-

 

1. The lower jewel is installed with lubricant sink towards the shaft. All others in this movement seem to be installed with oil sink away from the shaft end (please see photo below). The jewel is the type which has a brass cover, shield and single retaining screw.

493075b0c9737277daf9393e287b278f.jpg

1f7e83cccea84350422dacd38085057d.jpg

 

2. I am suspicious that the shaft end which engages in said jewel may have worn or even snapped off as there is but a small pimple of small diameter shaft evident. Is this correct? Please see photo (excuse quality). I am unable to photograph it through risk of damaging the hair spring, but the shaft mating with the upper jewel does seem to be slightly longer longer.

 

127709ee1007265be71e590b7b723aba.jpg

 

Would very much like your comments as to whether the jewel is correctly installed and also if the shaft looks damaged. Thank you all in advance. [emoji6]

 

 

 

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Deggsie WRT Addict

Deggsie

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Yepp . That is a snapped pivot  You need a new balance. Send me a PM. I could help out there i think? 

Super. Thanks for your quick reply. I'm just going to work out how to send a pm and I will do so. I take it that means private message?


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rogart63 Distinguished Member

rogart63

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Super. Thanks for your quick reply. I'm just going to work out how to send a pm and I will do so. I take it that means private message?


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I can take a look tomorrow if i have any balances for AS 984. And then send you a PM. Can take a fast look right now. 

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wls1971 Distinguished Member

wls1971

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You almost there with your diagnosie of the problem, you have correctly identified that the balance has too much play and is not sitting right in the lower jewel that is because it has a broken lower pivot and needs replacing, but that would require the correct tools to replace, or the other option is replacing what would be termed the "balance complete", staff, balance, hairspring and roller as a complete unit. the jewel is a cap jewel and is held as you say in a holder held in place with the screw.

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wls1971 Distinguished Member

wls1971

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If your changing a balance complete you should not need specialist tools beyond screw drivers and tweezers if rogat63 hasnt got one available there are some listed on ebay,

http://www.ebay.co.uk/itm/AS-Complete-Balance-Cal-984-Part-721-/222463092761?hash=item33cbd56819:g:dWYAAOSwB-1Y45Bw

or you could find a donor movement

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Deggsie WRT Addict

Deggsie

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Hello WLS and many thanks for your reply. So the lower jewel is fitted correctly then? If the lower pivot has broken, I will need to strip every last screw to make sure all fragments are eliminated from the movement. That'll be fun. Hi does the pivot snap? Must take quite a shock I imagine?


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jdm Distinguished Member

jdm

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Hi does the pivot snap? Must take quite a shock I imagine?

Not really, considering that there is no anti-shock in your mov.t,
I suspect that when these became common, many watch repairers became.. upset.

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