Hi Guys, this isn't actually an Omega watch, it's an old English chain fusee pocket watch, but the principle for all watches is the same. I thought I would share the process of making a balance staff for a watch for which parts are no longer available. Hope you enjoy.

I recently had a very old English chain fusee pocket watch come in. The watch needed a new balance staff because of a broken pivot. Due to parts not being available, I had to make one with my lathe.

Here is the lathe that I use. It is an 8mm G. Boley watchmakers lathe with a variable speed motor.


Before we can start on the new staff, the old balance staff must be measured so we know what size to make the new staff. I measure and draw a rough sketch.


Next, I use 2mm blue steel and mount it in a lathe collet. This is how our balance staff will begin its life.


I start to turn the steel down to size in the different sections.


More turning on the lathe.


We can see that the staff is starting to take shape.


Now we are really getting somewhere. The first pivot has been turned and the undercut has been turned so that it can be riveted onto the balance.


Once the one ended has been completed, the other end must be turned. We need to turn the staff in one sitting otherwise the workpiece won’t be true.


More shots of the balance staff.


More shots of it starting to take shape.


A few more.


I now start to turn the bottom pivot.


It’s crucial to go very slow and carefully at this point.


The pivot is almost there. A few more turns and it will be ready to part off.


Once parted off, the pivots are cut to size to make sure it fits between the plates. I will then mount it on the balance and polish the pivots.


Here is the staff next to a Canadian 10 cent coin for scale.

 

Thanks for posting this. It is always good to learn more about what the real watchmakers have to do to keep old watches in good working order.

 

Just amazing!!! Thanks again for sharing!

 

Wow, that's some serious skills!

 

Lovely!

Btw, what’s the pivot diameter? I’m assuming you meant 0.06 mm.

 

Great pics and work,
kind regards Max

 

This made my day! I have had so many watches with broken balances. Nice to see that someone can fix them!

 

That's amazing work there!

 

Very interesting to see. What is the total time taken on a job like that?

 

Yep, you are correct!

 

Wow, respect. Thanks for sharing.

 

I'm not familiar with machining at this scale. How limited are you on cutting pressure when cutting so narrowly? Are you very constrained in maintaining rigidity without tailstock support? The rule of thumb I've seen in larger machining is to turn between centers when the piece is longer than 2-3x the radius; here you're turning with a piece which is twice that far from the chuck.

Thanks for sharing!

 

Very interesting. Presumably the tool is held in the hand using the post for support? I can see it would need another pair of hands to take photos while actually doing the work.

This is as small as I go in lathes....

 

Yes, this is more like cutting on a wood lathe than it is an engine lathe. Typically no calculations for feeds and speeds, so all those formulas I learned decades ago all go out the window. This is highly reliant on feel and looking at the chips coming off as you turn freehand...it actually sounds more difficult than it is, at least in my experience.

 

I was wondering about that as well, and it also explains the finish.

 

The finish on the majority of the staff isn’t hugely important, so as long as it’s not too crude, it will be fine at the rivet, collet, and roller table. Of course it doesn’t hurt to make it nice and shiny either.

The pivots on the other hand are very important, so if done properly they are left slightly oversized on the lathe, and burnished to size on the Jacob tool, and this provides a very good finish and some work hardening as well.

 

Trying Guuuuuugle to find out what a "Jacob Tool" might be I came across this wonderful range of equipment




http://www.lathes.co.uk/georg-jacob/

 

Sorry, damned autocorrect....it’s Jacot tool.

 

You can polish the actual piece if you like, but a neat tool finish is fine on a balance staff. As Al stated, the pivots are the important part.

The cutting pressure needs to be extremely light when you get to the final pivot, as you are cutting a very small piece of steel at that point and if you aren’t careful it will break off.

You can also turn a balance staff between centres and use a hand wheel to power it. This is actually the way we did it at school. I find cutting in one operation to be a much faster method though.

I use a mixture of High Speed Steel and tungsten carbide cutting tools which are shaped to a diamond.