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Proper Way To Adjust Tight Balance Bridge

everydaycats

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Aug 11, 2011
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Hello all, I have been working on an old Caravelle with a 11dp movement. It started out as a non runner. After cleaning and oil it works great until I tighten the Balance Bridge screw the last 1/4 to 1/8 turn, and then the Balance wheel stops.

I cleaned and oiled both upper and lower jewels—this movement has an odd small internal spring with a tiny jewel under both upper and lower jewels. The pivots are in good shape. As I tighten the final mm on the screw the Balance will stop. I am now looking at either a slight bend adjustment of the bridge, or a shim.

In the past I have seen the old guys gouge a slight bit of metal as a shim, but I do not want to do that. I have used a double layer of Aluminum foil under the balance bridge before and that seems to work.

Any suggestions as to the best solution? I have removed and switched both upper and lower jewels and springs, but still no help.

Any advise would be appreciated.

Regards...
 
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gmorse

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Hi everydaycats,
Any suggestions as to the best solution? I have removed and switched both upper and lower jewels and springs, but still no help.
Do you know whether the balance staff is original or a replacement? Because that's probably where the problem lies, as long as the jewels are correct and properly seated, and if there's no evidence of any gouges or shims under the balance cock foot.

Regards,

Graham
 
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everydaycats

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Aug 11, 2011
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Hi everydaycats,


Do you know whether the balance staff is original or a replacement? Because that's probably where the problem lies, as long as the jewels are correct and properly seated, and if there's no evidence of any gouges or shims under the balance cock foot.

Regards,

Graham
Interesting and probably the problem. The original plate had the good balance. I had a spare parts movement with a broken pivot on the balance. The parts movement looked better so I used it to rebuild the watch. Therefore the balance does not match the plate, and that is probably the issue.

Also if you notice the original train bridge does not have jewels and the replacement I used does. I though the original train bridge was missing the jewels, but if you look at the pics in this tutorial(attached PDF) you will see the train bridge matches my non jewels original, so I have no clue what is right or wrong since they are both 11DP movements. However, one movement is clearly marked 17 jewel and the other 7 jewel—Just noticed that looking at my picture.

But I am going to transfer everything to the original plate that matches the working balance and see if that fixes the problem.

Thanks for the advise because I suspect it is the problem. I will reply again when the transfer is complete.

Regards

IMG_4309.jpg
 

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gmorse

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Jan 7, 2011
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Hi everydaycats,
However, one movement is clearly marked 17 jewel and the other 7 jewel
The seven jewel model will still have jewels on the balance staff, but whether they're the same as those on the seventeen jewel one I don't know; sometimes the staff dimensions are different on the different variants.

Regards,

Graham
 

darrahg

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If everything appears correct and the jewels are properly seated under the 'safety' springs, I will shorten the pivots to solve the problem that is described. I will not add tick marks and don't care for shims to raise the cock unless it is for testing purposes.
This situation is not uncommon with older watches as balance staffs can vary somewhat (depending on the company) but your watch is a newer type and I would be checking whether the jewels are correct and properly seated and, whether the balance staff, as well as the balance assembly, is correct for the movement. Another thing to check is if the pivots are too large for the jewel holes. Remove the cap jewels, one at a time if necessary, and see if the associated pivot projects through each jewel.
 

everydaycats

Registered User
Aug 11, 2011
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Mexico Beach, FL
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Hi everydaycats,


The seven jewel model will still have jewels on the balance staff, but whether they're the same as those on the seventeen jewel one I don't know; sometimes the staff dimensions are different on the different variants.

Regards,

Graham
Ok, moving everything back to the original 7 jewel plate solved the balance problem, but then encountered an escape wheel problem with it binding. I switched the escape wheel—at this point parts are mixed so not sure if it was 7 or the 17 jewel escape—and now running fairly well. Amplitude is a bit low, but for my purposes it's ok. I cleaned the lower and upper cap jewels as well as the tiny internal spring jewels. Those springs are a bear to get back in place. I have the 17 jewel train bridge installed now. Regarding the comment about switching the balance and not the cock—I simply used the original 7 jewel balance as it was in good shape. Ok, I'll watch it for a couple days and put in on the graph later...Here's a short slo-mo video:
 

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