Does anyone have a chart that I can use to measure a pivot size vs. the metric or inch equivalent. I have a nice set of Mitutoyo calipers that I can measure accurately with but I don't know how to convert to "hole" size or "pivot" size. I need this so I can accurately order a balance staff. I can't seem to find a gauge anywhere to purchase.

Thanks!
David

I may have answered my own question - the top measured .11mm and the bottom measured .09mm. I'm assuming that would be the pivot sizes. Now - when you order a staff they only give one pivot size - would that be the cock size hole or the bottom hole?

Thanks again,
david

Oh - by the way, this is for a burlington/illinois 19j getty model 16s balance staff. If anyone knows the part number that this would be, that would be helpfull.

Thanks!
David

I would expect that the bottom pivot is worn down to .09--unless someone modified it. Also,the lower pivot would be excessively loose in the jewel. I don't recall if any balance staffs had different pivot sizes, but if so, someone here will probably know.

I agree with Sam. The bottom pivot is likely worn down unless the lower jewel was replaced at some time with one with a smaller hole.
The "Swigart Manual" lists two staffs for the models 4 & 5 (Getty) #47606 and #47609. Below are the dimensions of each from a chart posted some time ago by John Duvall.


Hope this helps you

In my haste the headings in the above chart are misaligned. The last four should be shifted over to the right but since it is a gif image rather than text I can`t edit it easily.

This diagram may make it a little clearer.

Thanks!!!