"Harold & Susan Vordos" wrote in message
...

That's what I meant, sort of round about. My experience in the missile
industry taught me that one was not free to stab a hole in any part and
call
it good.

Who has that luxury?

While holes often had a specific tolerance, there were times when
they did not. In that case, QC reverted to specific standards, in my case
to MIL specs.

It is rare that I see a drawing without a general tolerance guide in the
title block.

My point in posting what I did was that it's a good idea to
double drill holes *because* one is likely not free to end up with holes,
size be damned.

Well, application is important. I drill a lot of clearance holes for screws
in the dies at work. Sometimes the holes are greater than 400mm deep,
perhaps Ø16mm+. In this instance, the diameter is pretty loose and the holes
are too long and numerous to double drill.

Of course, the panels produced using our dies require very specifically
sized holes.

You just told me the same thing, only supplying the
references to which you must work. Do you wonder how many have ever
considered that holes must be held to a specification?

That doesn't even register. There is always a specification/tolerance.

Regards,

Robin