On Mon, 19 Jan 2009 19:11:41 GMT, "Ivan Vegvary"
wrote:

Simple question. If you bored, say, a 1" diameter into a part mounted on
your lathe, and then wanted to do an accurate chamfer, how would you go
about measuring it. Say you want to chamfer out at 10° and the resulting
slope is to extend 1/4" into the bore. I know how to set up the tooling,
BUT, how do I precisely measure the 1/4" "daylight point".
Alternatively, I could simply figure the increase in diameter at the working
end. (tan 10°x0.25)x2. Okay, so now I know that the new diameter should be
1.088". How do I measure that. Seems like measuring this larger diameter
would end up to be an 'eyeball' job. My eyes are old.

Ideas with how to proceed would be greatly appreciated.

Thanks,

Ivan Vegvary

Same way you measure the diameter of a countersink. Put a ball into
the hole and measure the height of the ball above the face of the
bore. Do a bit of trig and you can derive the diameter of the
countersink.

Regards, Marv

Home Shop Freeware - Tools for People Who Build Things
http://www.myvirtualnetwork.com/mklotz