HowTo: Replace a balance staff

IMG_7865I normally don’t do this (e.g. just replacing a balance staff without fitting it into the movement), but Thom asked nicely, so I took on the job. If he would have lived in the UK, I would have invited him to do it himself in my workshop, but Sweden is a bit far …

I used to turn the old balance staff out on the lathe, but I never liked the process, as it’s so easy to get the graver into the balance…

So finally, I invested a lot of money into a Bergeon Platax tool, which allows you to chase out the old staff without using the lathe. Great stuff!

In the first setting, you remove the roller from the balance as shown in the photo above.IMG_7866

In the second setting, the balance wheel spokes are firmly held down by a stake, and then a punch knocks out the staff.

Once you have done this, you will never go back to the lathe, as it’s easy, safe, and the chances of damaging the balance are far lower.IMG_7867

Click on the photo to enlarge it. No damage whatsoever to the balance, and a clean cut edge on the old staff. Worth the £400 for the tool if you replace staffs.IMG_7868

Now it’s over to the staking set, and this is my brand-new Star. First use! To start off, I find the right hole for the balance staff.

The old Pearl will go into retirement, but I will keep it if I ever have to do something that might damage a stake.IMG_7869

 

Now I use the centre punch to make sure the hole is centred.IMG_7870

Now I find a flat and a rounded stake that just fit over the staff.IMG_7872

I start off with the flat stake, to make sure the balance sits level on the new staff.IMG_7874

Now I use the rounded stake to rivet the balance staff onto the balance. Slowly does it. I use light hammer strokes, and lots of checking. In between, I use the flat stake again to make sure everything is level.IMG_7875

After a bit of riveting, the staff finally starts gripping, and is now firmly riveted to the balance.IMG_7876

And now you can see why I bought the Star staking set with the additional bottom bit. This allows you to use stakes as anvils, so I can rest the rivet of the balance staff on a stake, whilst pushing on the roller.IMG_7878

The roller is back on.IMG_7879

Last but not least, I put the hairspring back on, and the job is done. The balance goes back to Sweden.

11 thoughts on “HowTo: Replace a balance staff

  1. Hi Christian, that’s a lovely little tool and a great demonstration, thanks!

    Would you need to poise after a operation like this?

  2. This is a fantastic post, Christian. Really enjoy learning more of the art and appreciate your time in producing such a resource! I know they take a bit longer, but any time you get the itch to write a tools and techniques post, know that you’ve got an eager and appreciative audience.

  3. I’m curious, when attaching the roller, how do you reposition it in the same location relative to the balance? In other words, do you mark the balance first? BTW, I appreciate your site and work. Quite impressive.

    • Hi Dan,

      The roller always sits with the impulse pin at 90 degrees to the spokes. I take a photo so I know which side it sits on. You can also deduct the position from the mark for the hairspring stud on the other side.

  4. Hi Christian this is my first reply on your blog, but have been reading since you started.I am a amateur watch maker and always learning something new, love the site keep up the good work. This is the best photos i have found of the before and after of the platax tools work, very surprised at the lack of damage to the balance wheel. I think i will now try and source a used one as they are expensive new. PS love the new workshop good luck for the future.

  5. Very interesting, that seems a large investment in tools for what the ignorant (me) might assume was a fairly straightforward job. I’d have just thought the staff was pressed in by hand – is a lot of pressure required? and accuracy obviously paramount?

    • You can put the staff in by hand, but it then needs to be riveted into position. You can only remove an old staff with a graver on the lathe, or with the Platax tool.

      • Thanks, very interesting to see how it’s done. I’d love to see more like this, I find it fascinating!

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