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Posted (edited)

Re-assembling a Longines 30LS, I have a problem with barrel arbor endshake.
The endshake of the arbor  in the barrel is fine, but there is no endshake of the arbor when installed between the bridge and the mainplate. 

The hole in the bridge shows signs of having been closed at some time, which may have been the cause.
But, holding a straight edge on the mainplate and bridge, they both look flat to me.  

So the question is, what is the best way to get a touch of endshake ? 
Bridge (probably) or mainplate?  And the best way to do it?

 

 

Edited by mikepilk
Posted

The gear train does not run as freely as I would like, and the amplitude is lower than expected. I feel that just a small amount of endshake would make all the difference.  

Posted

As Hector said, the arbor end shake in the plate/bridge will not affect the running of the movement. It is important that the arbor will stay upright so the barrel will be not tilted and stay on correct distance as to ensure right mesh of the barrel with the pinion of the 2nd wheel, so wear of the holes in the plate and bridge is something bad, but not because of the friction. The arbor rotates only when winding.

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Posted
18 minutes ago, Neverenoughwatches said:

Same as Hector, the barrel unwinds about a static arbor. Barrel arbor only moves when the ratchet wheel turns it. 

D'oh. Silly me. Yes of course it does. I was tired and I'd had some nice wine 🤣

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