Help With Bulova Ladies Watch 6P

[Charlie]

I have been servicing a Bulova ladies watch, movement 6p. This is a mid to late 20's vintage watch. Watch has been cleaned, and oiled. Train is free, end shakes ok. Balance and hairspring are fine. I removed the barrel and cap, pushed down some coils along the outer edge of the barrel, and applied 9501 grease along the top of the coils. The watch rain great after that but after an hour or so stopped. I noticed I had left the crown and ratchet wheel screws to try and troubleshoot. I tightened those and it was running like a champ again. After coming back from an outing, it had stopped again. Balance moves very well while putting lateral pressure on one of the spokes on the center wheel, indicating power is not being transferred. I have checked to make sure the barrel cap is snapped down flush to the barrel. Arbor pivots are oiled. Does someone know of a common location to check for next? 

[bobm12]

Hi Charlie,

 

Although I am fairly new to this, not familiar with most Bulovas and never serviced a small movement of the kind women watches use, I would venture: how about the jewels? any of them cracked or chipped? Main spring slipping inside the barrel or unhooked from barrel axel/pivot?

 

Hope this helps,

 

Cheers,

 

Bob

[clockboy]

Is it a auto.  Had a similar problem with a ladies watch fitted with a Eta.  Changed the reversing wheels and put braking grease on barrel rim and the problem went.

Edited January 17, 2015 by clockboy

[Charlie]

Thanks for your input Bob. I always inspect the jewels during disassembly.

Clockboy, this is a 1920's piece. Hand wound with only two hands.

Well, I think I may have found the problem. There is obvious scoring on the bottom of the barrel bridge all the way down to the brass. I put a few very very tiny spots of blue grease right where the scoring is. I put the ratchet wheel back on and the grease was gone. So it seems like the ratchet wheel is contacting the bottom of the barrel bridge. The arbor is not protruding enough through the bridge to keep the ratchet wheel well elevated above it . The ratchet wheel thickness should be reduced here rather than file the barrel bridge, but I don't have my lathe set up. I might try a small dial washer over the arbor first.

Thank you both for your input.

Charlie

[Geo]

Hi Jerry, what do you think has changed to cause this situation? It doesn't seen right to thin down the ratchet wheel. Could there be a small washer/spacer missing?

[Marc]

Have you checked the barrel arbor pivot holes in both the main plate and the barrel bridge for wear? Excessive wear in either of these places can cause the arbor to tilt such that the ratchet wheel can contact the barrel bridge on one side. If this is the case then the correct repair would be to re-bush the worn pivot hole, although on something as small as this that may be quite a challenge.

[Charlie]

I think that may be what is happening, although the arbor barely protrudes the plate as well. The score marks are brass and are on only on one side of the barrel bridge recess on the bottom, which may point to the barrel being tiled.

[Charlie]

Marc,

I have checked the arbor pivot hole in the bridge but not the plate. The bridge hole is in excellent shape, I will be checking the arbor hole in the plate this evening. If it is quite worn, I would be tempted to install a jewel instead of a bushing, provided there is enough material to hold it firmly . There is a caveat though, this would be my first attempt and this is a friends watch.

Edited January 18, 2015 by Charlie

[Marc]

If you've got the equipment for installing friction jewels, and as you say provided there is enough room in the plate to accommodate it then that would certainly be a solution.

If you are unsure about the process Mark has recently done one of his excellent videos (vintage Omega 30T2) in which he replaces a badly worn centre wheel bearing with a jewel.

Also if you have an old main plate from a scrap watch or even a scrap piece of brass plate you could have a practice run on that before tackling the Bulova.

Assuming you have a jewel the right size the most critical thing is ensuring the axis of the hole doesn't shift from where it's supposed to be in the process. As far as end shake is concerned so long as the jewel is pressed flush with the train side of the main plate you should be OK, but this can be adjusted fairly easily.

 

Good luck, let us know how you get on.

Edited January 18, 2015 by Marc

[Charlie]

Thank-you Marc,

I have seen Marks videos on installing jewels. It does give the amateur much confidence to say the least. Excellent tutorial and it takes the mystery away from how to take the measurements and proper sizing. I own a complete Seitz jewelling set. I would perhaps order two jewels, one for practice and one for installation on the Bulova.

I wound the watch fully last night and it was running fantastic for a good half hour, with amplitude over 300. In the space of several hours, this amplitude deteriorated. When I awoke the next morning, it had come to a complete stop. It is temping to provide further clearance to the bottom of the barrel bridge to clear the ratchet wheel and look for any improvement. I may have to resort to this measure if the main plate arbor hole is found to be in good order like the barrel bridge arbor hole.