Dial Bore Gauge

Don't know if they will work or not. Just use an OD mic to set. Or a set of gage blocks, if you have the type that will connect with a screw and has end pieces.

Harbor freight has a mike holder for about 10 bucks that will hold the mike for you as you set up the dial bore gauge.

John

If it's the one I've seen in the ads, it's only got two diametrical contact points, not three, so either a set of gage blocks with ends or even a good mike could be used for setup. Rings are really only needed if you've got three contact points. I've got a few bore gauges like that. Hope you've got a temp-controlled lab if you're expecting good tenths measurements.

Stan

Depending on the tol. you are working to, bearing races make a good gauge to set your bore gauge. You have to check the spec for the bearing.

John

Or a set of compression frames and the long end pieces for the standard rectangular gauge blocks. I've got such a set (by DoAll) but I can't remember (if I ever knew) what it is called. A collection of telescoping frames of various lengths, and two extra long blocks (1" long between measuring surfaces, but something like 2-1/2" wide with a hole near one end for the pins which hold the end pieces into the frames to be clamped onto the stack of gauge blocks.

Enjoy, DoN.

Just use your vise, wrap a shop rag around the shaft and clamp LIGHTLY so you can set it with a mic. That will hold the bore gage steady to find the smallest reading.

One of the cheap Chinese gauge block sets should suffice. They are within +/- 0.000050", so with worst case, you could get a ten-thousandth ("tenth") error for two blocks stacked, and in all probability, the errors would mostly cancel. The surface finish on the cheap Chinese block sets is poor enough so they don't "wring" well, but it should work well enough for your purposes.

Out of curiosity -- what is the resolution on the dial gauge? If it is to tenths, you are probably within reason, if it is to thousandths, you are unlikely to make a stack of blocks tall enough to reach the resolution of the dial gauge.

Good luck, DoN.