Jump to content
  • 0

BFG 866 - Balance Help!


Question

I had great success today stripping, cleaning and rebuilding a Baumgartner BFG 866.

However, when cleaning the balance, the spring somehow separated from the bridge....... I couldn’t work out how so attempted to simply bend the small pin that holds the spring in place and managed to snap it clean off 😩

I can see the parts a readily available on cousins so I can buy a new balance bridge, however, can someone tell me the correct way of re-installing the balance wheel/spring without having to bend the little pin?

5C2AF3C9-61F8-45EC-A060-6DE92ADCB9E5.thumb.jpeg.631c51f51836acea0079b97c23273422.jpeg

 

Link to post
Share on other sites

7 answers to this question

Recommended Posts

  • 1
43 minutes ago, Robbie010 said:

how do I refit the spring / balance wheel without bending this pin?

Please read again my previous answer. The points that fully answer your question are in boldface.

  • Thanks 1
Link to post
Share on other sites
  • 0
53 minutes ago, Robbie010 said:

However, when cleaning the balance, the spring somehow separated from the bridge....... I couldn’t work out how so attempted to simply bend the small pin that holds the spring in place and managed to snap it clean off 😩

What you circled is called regulator (index), it doesn't hold or guide the hairsping but just regulate the rate by changing its effective length. This regulator has one curb pin which faces another part called boot, which can be rotated to ease the hairsping in or out.


Incidentally, the pin that actually keeps the hairspring attached to the balance cock is still there, wedged between the end stud and the hairspring.
 

The last observation is that unless you know for sure that the part can take it, never try to bend or otherwise force watch parts. A breakage is the usual result.

  

  • Like 1
Link to post
Share on other sites
  • 0
10 minutes ago, jdm said:

What you circled is called regulator, it doesn't hold the hairsping but just regulate the rate by changing its effective length. This regulator has one curb pin which faces another part called boot, which can be rotated to ease the hairsping in or out.


Incidentally, the pin that actually keeps the hairspring attached to the balance cock is still there, wedged between the end stud and the hairspring.
 

The last observation is that unless you know for sure that the part can take it, never try to bend or otherwise force watch parts. A breakage is the usual result.

  

Sorry, poor explanation. I found this picture from a previous post that better explains the issue. The small pin circled in red has snapped off. 

As you can see in this image, the pin seems to act as a guide for the spring so if I buy a new bridge (with the pin and boot in place), how do I refit the spring / balance wheel without bending this pin?

61F0B4E5-F843-4DAF-BCD2-42D40597F4A3.jpeg.f4a6d8633c6d5fda3cd1bcea21f0b245.jpeg

Link to post
Share on other sites
  • 0
7 minutes ago, canthus said:

You can get these parts from Cousins UK

Which is good, although in my opinion replacing a curb bit is delicate work which can be beyond a beginner. 

Also worth to note, if one orders a balance cock, will not receive these parts, which are instead in the regulator index assembly. 

Link to post
Share on other sites


  • Recently Browsing

    No registered users viewing this page.

  • Topics

  • Posts

    • Not all mainsprings are coated some of them supposedly because of the alloy they don't need Teflon or anything. But you still caught with the same problem basically it's invisible. If you clean the mainspring and it had an invisible lubrication it now does not. The problem with invisible lubrication is you don't know it's there. Which means if you clean it you remove it but since you don't know if it's there or not that doesn't matter. If the mainspring has old oils are greases they definitely have to come off because they will be sticky. if you have a nice clean mainspring it should be lubricated with something. Just don't get carried away with putting too much on otherwise it leaks out of the barrel.
    • Thanks again. They explain the process pretty well and are a great help. Took the back off the watch tonight for a quick look and thanks to the manuals confirming, I need to get my hands on a crystal lift tool before I go any further. 
    • A question that comes up all too often is problems related to hairsprings. Seems like a simple solution the hairspring is removable they can be swapped. But you're going to end up with timing issues each hairspring comes with its balance wheel it's why they're not sold a separate components they come together. I'm attaching a PDF it's not for your watch I want you to go to the very last page. The very bottom of the last page look at how they hairspring looks? Compare that with your hairspring they don't quite look the same. I don't think your hair Springs been destroyed I think it can be fixed but it can't be fixed if you don't grasp what it's supposed to look like. Then even if you grasp what it's supposed to look like hairspring work requires a lot of time to learn. Like everything else in watch repair it requires a heck of a lot of practice. You really should be practicing bending hairsprings every single day preferably not in a watch something disposable. Look on eBay look for cheap movements  Something a don't care about something to practice with because without the practice trying to practice as you go on the watches are working on is not a recipe for success. The reason for the PDF is the last page talks about the etachron system which adds complications perhaps. So the problem is at least for me it's hard to tell where the problem is with your hairspring other than the problem is very visible.  This is because it could be a bend of the hairspring or if the etachron  stud for instance has been rotated and you're not quite the right place that is not be a problem also. Or more likely you have both problems. Seiko 7S26C_36C.pdf
    • Buttoned back up and ticking away nicely. I wonder how many of these are still running? Some Metamec history.  
    • Right. Moebius 8200 is a good option.
×
×
  • Create New...