I need to measure the diameter of several shallow blind holes in bottom of a 6061-T6 valve body to +/- 0.0002 accuracy. The holes are nominally 0.060" deep and 0.625" diam. The holes are at the bottom of a 1" diam bore about 1.5" deep. Since I can't reach them with my inside micrometer I was thinking of buying several Go/NoGo rods in0.0002 increments either side of 0.06250". Since I have not used Go/ NoGo's for such small increments on aluminum I don't know if this will be an impossible task, ie. if the rod is not perfectly square to the bore I might get a NoGo when in reality, I should get a Go etc. Anyone care to comment? Since this is for only a few parts now, and possibly very light QC type use later, any measurement scheme that costs more than a few hundred bucks might not be worthwhile.
15 years ago