Using a Vertical Bench Micrometer to Measure Balance Staff

[jdrichard]

I think I have figure out how to use my new vertical bench micrometer to give me all the exact measurements needed to cut a new balance staff.

I have included a sketch of what is easily measurable with this tool, and with simple math the other cuts can be determined. The Tavannes Vertical Micrometer has a very convenient table, much like a staking set table, that allows you to place the balance in and under great control measure the stepped dimensions. Se the following pictures.

Edited February 3, 2021 by jdrichard
Added picture

[nickelsilver]

Yeah it's the tits for that kind of work. If you just have one broken pivot 9/10 times the length from pivot end to end of conical shoulder is the same on both sides so you can fill in the blanks. If both pivots are gone, meaure between uncapped jewels of balance bridge to plate and you're in a 0.05mm ballpark, cut slightly longer and adjust pivots as needed. I usually cut them to the measured size and it's on.

Until I got a measuring microscope my vertical mike was the go-to for staff work. The microscope gives a little edge but not much. Shines more in picking up dimensions when reverse engineering other parts.

[jdrichard]

21 minutes ago, nickelsilver said:

Yeah it's the tits for that kind of work. If you just have one broken pivot 9/10 times the length from pivot end to end of conical shoulder is the same on both sides so you can fill in the blanks. If both pivots are gone, meaure between uncapped jewels of balance bridge to plate and you're in a 0.05mm ballpark, cut slightly longer and adjust pivots as needed. I usually cut them to the measured size and it's on.

Until I got a measuring microscope my vertical mike was the go-to for staff work. The microscope gives a little edge but not much. Shines more in picking up dimensions when reverse engineering other parts.

Do you have a photo of your measurement microscope?

[nickelsilver]

I'll get one tomorrow

24 minutes ago, jdrichard said:

Do you have a photo of your measurement microscope?

 

[nickelsilver]

That's the measuring scope. The table is on ball bearing slides with zero play or backlash, the micrometers that move the table read out in 0.001mm. There are several objectives but I always use 50x, the eyepiece has cross hairs and concentric circles making it easy to line things up. For a balance or other wheel, I hold it in a tiny vice (it's about 1.5 inches long, with 15mm jaws) so that the staff/arbor is horizontal. Line it up with the X axis- the table rotates- , zero on one end, then take all the measurements. For a staff I take all the measurements with the balance still on, which means I get everything except the rivet height, which I get after cutting the staff out measuring the balance thickness. A really nice thing about taking all the length measurements like this is you have one start point, so you don't stack up errors which can make a real difference in the total length. Same is true with the vertical mic, but you will have two start points. As long as you know the total length you want it's just a matter of averaging out any discrepancies.

 

These can range in price from a few hundred bucks to quite a few thousand. In North America a couple of brands that are little known but very high quality are Unitron and Opto-Metric. Opto-Metric was mainly an importer of Leitz and other brands but sometimes a scope will get listed on Ebay as simply Opto-Metric. That's when you can get a real steal on one. Most of the big microscope makers made them, Nikon, Leitz, Olympus, pretty sure Canon, then Mitutoyo and some other measuring tool makers as well.

I use mine every single day, I love it. It also gets used a lot to check pallet stones prior to moving and after moving them, so that I know for sure how much they moved.