"Ace" wrote in message
news snip----

I once had the occasion to check on "parts out of tolerance". The drill
press operator
showed me in black & white, "drill #30 thru". And of course he had
correct
drill, but it was
so badly worn, it was drilling way undersize.... But, according to print,
he was not at fault.

Where I was trained, he would have been. That's the point. Unless
otherwise specified, there were standards to which we had to drill holes..
QC made sure we did. Do keep in mind we worked to MIL specs, however. We
were engaged in building a missile. The tolerance block on the print did
not apply to drilled holes aside from location. Hole size was dictated by
a standard with an ever increasing tolerance, according to hole size, and it
was far more restrictive than the block tolerance. It made sure that a
hole could not vary by going much undersized, and was relatively tight for
oversized. To me, it made sense. In today's throw away society, with a
bar that has been lowered below ground level, perhaps it no longer does.

Harold