thanks Tom those are pretty much my thoughts as well. do you ever scan the bore or just do individual shots? i can't help but think scanning is better the only exception being it won't tell you at what height the thinnest spot is.

Dustin that's just gross

the problem is unless it's a complete circumference of bore i have no way to machine it to a uniform thickness. if i had a full piece i could turn it on the lathe. i'm probably over thinking this as far as calibration i'm just not crazy about calibrating the probe on a flat piece but in reality you have to calibrate the probe to the mic first and the only way to do that is with the flat disc that's mounted to the mic anyhow