Thread: Ball gage, ala van keuren lapping kit

One of the items that came with van keuren micrometer lapping kits was a ball tester: two different precision gage balls held captive in one little rectangular piece of metal. The ideas was you lapped your anvil and spindle flat, then used the gage to ensure consistent difference between the two surfaces. Two sizes allowed you to test the mic at different spindle settings (e.g., 180 degrees apart).

Does anyone still offer these? I can buy the balls, but the handle would be convenient.

Jim

Why not use a optical flat?

An Optical Parallel set might be a better choice.

Mitutoyo sells a set of four that are about an inch in diameter specifically for checking micrometer parallism.

Jim --

Don't know if anyone is selling a commercial two-ball micrometer tester or not, but a shop-made version can be as simple as a tab of 3/16 inch thick leather or rubber belt (or sheet) with nearly-1/4-inch and nearly-5/16-inch holes punched through. A bit fancier version uses a drilled metal bar in place of the leather, with a couple of center-punch "pops" near the hole edges to retain the balls.

John

All,

Thanks for the notes. As background, I just got a vintage Van Keuren micrometer lapping kit. I'm interested in is using a physical measurement to check, to see how difficult it is. Intellectual curiosity, plus an "old school" bias.

I do have a set of Mitutoyo optical flats, the ones that allow you to check the anvil and spindle faces at 90° (for inch/imperial at least), and a monochromatic lamp. And I'll use those, but I wanted to see if ball testers such as those described by John were available. It's what came with the van Keuren kit.

I think John's suggestion is what I will follow up with - I hope my punch "pops" are light enough not to damage the balls!

Thank all.

Jim