Granted working to the max or min tolerance is a problem and should never be done.
One of the toughest things to instill into the production mind is that they do not "own" the full print tolerance. The only people who "own" the full print tolerance is final inspection, as that represents the customer's dock OR (if one ignores some measurement error) 100% inspection. Manufacturing is restricted by the virtue of their sampling error, measurement error (no matter how small) at a minimum. The first thing I hear is "You are cutting my tolerance!" Guess what, you never had it - you just didn't realize it. That is one reason why they shy away from SPC, it appears to "cut their tolerance." Again, you never had it. If you want it back, all you need to do is 100% inspection! Sorry for your luck.
But the good news is, once they figure it out, 0.000001 is a non-issue!


