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Posted

I've got a 1920s Jaeger car clock with platform escapement that I need to make a new balance staff for and tonight I will measure the broken balance staff to get all the critical measurements.

Previously I have just made a rough hand drawn sketch of a balance staff but decided it would be nicer if I had a good diagram I could use to write the measurements on and then keep it filed away should I ever have to make another ABEC balance staff.

I was thinking of making one up in CAD from scratch but in flicking through Henry Fried's book 'The Watch Makers Manual' I found a perfect diagram.

Took a photo of it, did some clean up  of it in GIMP and then turned it into a PDF file for easy printing. I have set the PDF to be A4 size.

I have attached the PDF and a JPG of the image too as I thought this may be of use to other people.

If you haven't already got a copy of Henry's book I do recommend it, as in my opinion it gives the best walk though on making a balance staff using only the equipment an average watchmaker would have in their workshop.

Balance staff6.jpg

Balance Staff.pdf

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Posted
I've got a 1920s Jaeger car clock with platform escapement that I need to make a new balance staff for and tonight I will measure the broken balance staff to get all the critical measurements.
Previously I have just made a rough hand drawn sketch of a balance staff but decided it would be nicer if I had a good diagram I could use to write the measurements on and then keep it filed away should I ever have to make another ABEC balance staff.
I was thinking of making one up in CAD from scratch but in flicking through Henry Fried's book 'The Watch Makers Manual' I found a perfect diagram.
Took a photo of it, did some clean up  of it in GIMP and then turned it into a PDF file for easy printing. I have set the PDF to be A4 size.
I have attached the PDF and a JPG of the image too as I thought this may be of use to other people.
If you haven't already got a copy of Henry's book I do recommend it, as in my opinion it gives the best walk though on making a balance staff using only the equipment an average watchmaker would have in their workshop.
162482250_Balancestaff6.thumb.jpg.aea6e2d227b98e769c0a6f7138e2743b.jpg
Balance Staff.pdf

Thanks


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Posted

I do about a staff per week and have honed things a bit in a couple of decades. One thing I'd modify on the drawing above is how the measurements are referenced for the lengths. I find it's good to have a start point, and work from there as much as possible. In the little sketch below the tip of the pivot is "zero" and all the lengths are referenced from there. This helps avoid stacking up errors, where if you were individually measuring the length of the balance seat, hairspring collet diameter, pivot etc. even if being very careful you can end up surprisingly far off on the total. In my case I rough them out with a cross slide so while I have lengths referenced from right to left for everything, there is a second set of lengths starting from the hub for the lower half. If I was flipping the staff to work the bottom I'd do new lengths referenced from the lower pivot.

jlc staff.jpg

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