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Baumgartner BFG 866 movement help needed

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3.3K views 7 replies 3 participants last post by  Bill M.  
#1 ·
Hi!

I need a bit of help understanding how the Movement of the wheels are transferred to the hour and minute hands. I've done a bit of searching on how these infamous movements work and I did find out some info.
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Basically the watch runs, but the hour and minute hands do not turn. My first instinct was to think about the cannon pinion, but discovered that it is not press fitted to the minute wheel post. The center post is riveted to the top main plate, and the second wheel pivot goes through this post.

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Then I read that the friction needed to turn the wheels and hands is provided by the secondary wheels connected on the main spring barrel plate. This wheel seemed a bit loose, not snug enough to turn the wheels that the hands are attached to.
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Okay, I think I know what needs to happen. The clutch(?)on this assembly needs to be tightened onto the plate with enough friction to turn the hands, but need to be loose enough to turn the crown in hand setting mode. Am I correct?

If I'm on the right track, I need to know how this is done. that's my question. Will I need my staking set for this?

Thanks for any help!
 
#3 · (Edited)
Thanks for the reply, appreciated.

I've dug around some more on a watch repair forum, and found a post where a enthusiast like me posted very detailed instructions on how he went about tightening this assembly. Yes, I'll need my staking set for this.
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The underside of the top plate where the arbor fits needs to be supported. This is attached tight, while the top of the tube is flanged outward to hold the wheel with just the right amount of friction.
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A conical punch with center hole should be tapped very lightly to spread out the flange just enough to allow a bit more friction to turn the wheels in time keeping, yet be free enough to turn in hand setting. The same principle as the friction on a cannon pinion.

I'm posting this here because I'm happy to learn this type of skill. I hope it helps someone else someday. I also know that these BFG866 pin style movements aren't considered high value or quality, but if no one else wants to work on them, at least I'll have gained a little bit of knowledge on how they actually work, and improve on my fault finding. It's fun as well. If I mess it up, not a big loss.
 
#5 ·
Bill M. said:
Very cool!
I rebuilt one of these several months ago and had to do same as you, turned out nice.
I found a great technical walkthrough on the Watch repair talk site”Baumgartner BFG 866 - Removing centre seconds wheel
Click to expand...
Yup, This is where I found my info through a quick search. I couldn't read his page where he details this procedure in pictures (no longer available) but he described it in a thread, which really helped!

I need to remember to bring my staking set back home. I've been using it at my work for indicator repairs.
 
#6 · (Edited)
Mr Dennis said:
Yup, This is where I found my info through a quick search. I couldn't read his page where he details this procedure in pictures (no longer available) but he described it in a thread, which really helped!

I need to remember to bring my staking set back home. I've been using it at my work for indicator repairs.
Click to expand...

I might have it in PDF. If your interested.
 
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