Olin Lathrop wrote:

> R. I. Nelson wrote:
>> You have the margins set with a tolerance of  +-0.0005".
>> You have the tools to read to 0.00005".  You have apart that is
>> supposed to be 1" DIA.  It measures  1.0000" with calibrated mics any
>> one with common sense can call that a 0 tolerance part.

I'd say you can call it a "1 inch part" without further going into details,
because a diameter that may vary from 0.99995" to 1.00005" is close enough
to 1" to justify that name, in most contexts, and specifically in your
context (where the required tolerance is bigger than the actual tolerance).

But don't call it a "0 tolerance part": you even /know/ the tolerance...
it's 0.00005", not 0". So why call it 0 if you know it isn't? What you seem
to try to say is "it's as close to the target as we can get with our
tools". But that's a long shot from "0 tolerance"... and "0 tolerance" in
this context sounds even a bit arrogant, in the sense of "our tools are the
best, and we are so close to the target that nobody can measure a
deviation". (Which, even if it were true, would still not create a "0
tolerance part" :)

> There's enough public misundertanding about this concept that it's
> important (in fact irresponsible not to) for us engineers and scientists
> to state it correctly.  

Olin's point about making sure the public (and that includes lawmakers)
gets a better understanding of what we do and deal with is quite important,
IMO.

Gerhard

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