Hey guys, I would like to have your opinions and experiences on this topic.

Consider this, a Ø10 ±0.10 hole is toleranced with a positional tolerance of Ø0.05 at max material condition, for this example we'll ignore any datum references. If the hole is actually Ø9.88 (0.02 undersize) technically your positional tolerance should be reduced to Ø0.03 if the part is still going to fit with some other mating part. Normally, if a hole is out of spec it is fixed, but what if the customer accepts the hole a little on the small side, would you change your allowable tolerance to suit. I have seen it happen where the feature is accepted out of spec but the related GD&T is not altered to ensure that the part still functions.

I have my own opinions on this but I would like to hear others, thanks.

Bill Reilly
Quality/Technical Manager
Quality Inspection Technologies