Staff not at 90 degree angle to balance wheel

[JohnC]

Hi all,

I am a novice, so please bear with me. I am trying to rehabilitate a Bulova 8AH that has been neglected for what looks like many years. When I got the watch, I noticed it would run in the dial up position, but stop when dial down.

After removing the movement, I saw that the cause of the stoppage was that in the dial down position, the bottom of the balance wheel was grazing the top of the pallet bridge. I suspected a bent balance staff pivot, although it was clearly not broken.

Having cleaned the movement and inspected the parts closely, it appears that the staff is not bent, but is seated in the wheel at an odd angle. If I look across the balance wheel rim with the wheel held horizontally, the angle between the staff and the wheel rim is not 90 degrees. The staff and the wheel are not "square," if that makes any sense.

I am wondering what could have caused this, and what you recommend. I'm not advanced enough to attempt a balance staff replacement, so it seems like the only option is a donor. 

Thanks for your thoughts.

John

[JohnR725]

The most likely scenario normally would be somebody replace the staff and didn't true the balance wheel the way they're supposed to make it run flat.

The first link lots of interesting stuff scroll down to the section labeled Joseph School of Watch Making. Section 2 covers truing balance wheels.

Then the second link because I always like to see a picture of whatever somebody's working on. J

Third link cross-references for your discontinued balance complete

 

https://mybulova.com/vintage-bulova-catalogs

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Bulova_8AH

http://cgi.julesborel.com/cgi-bin/matcgi2?ref=[^[D_F[

[rodabod]

I might suggest marking the staff with a marker pen, holding the staff carefully in tweezers, and then see if the rim can rotate independently of the staff, which would indicate a loose fit. If it’s as trivial as this, then they can potentially be tightened with a staking set. 
 

Possible reasons for it becoming like this: heavy impact, or insufficiently strong rivet on the staff. 

[JohnC]

Thank you both very much, those are helpful comments. rodabod, I'll try rotating it and see if it is loose. I don't have a staking set, but I'm sure I could seek out someone to tighten it. If not I suppose I'll go for the replacement. John, I did not know about that website for cross-referencing parts. That's great, thanks!

[JohnR725]

3 hours ago, JohnC said:

I did not know about that website for cross-referencing parts. That's great, thanks!

If you want to be successful in watch repair cross-referencing parts or just finding the parts is extremely important in addition to that website there's another website unfortunately for this one there's a cost and you have to have understanding of the part numbers there is no pictures. But if you understand the part number system even run of a cross reference thing where you can get the part number and go and enter it somewhere else in the hotel you all the watches that use the same part similar to the other website

http://www.bestfitmaterial.com/

It's a shame though the website doesn't have pictures because originally they had a really nice two-volume book for looking up things for your watch. Then there is a PDF version of the book I purchased mine from the people at the website below but if he asked nicely other people will tell you where it's lurking out there..

https://mccawcompany.com/?s=bestfit

Also on the website above if you look around they have a page where they have datasheets can download. Although if you spend enough time looking for datasheets most of the places have the same sheets there aren't too many people that are actively scanning old sheets into the computer unfortunately