From: Bob Ranck <Bob@newsguy.com>
Subject: Re: what are these Mic's worth?
Date: 14 Jan 1999 18:42:02 -0800
You, Fitch and the others raise a lot of very valid points. But now I must
weigh in on this one.
My credentials: I am tool & Gage Supervisor in a LARGE machine shop.
I supervise Calibration and maintain over 5300 pieces of measuring and test
equipment, just in this one plant. We have nearly 450 comopany-owned OD
micrometers alone in this machine shop - Brown&Sharpes, Lufkins, Scherr-Tumico,
Mitutoyo, Starrett, and Craftsman primarily, and I won't even begin to hazard a
guess at the value (the largest ones go to 70 inches, $1400.00 per copy) but we
also have a lot of the individual operators who have brought their own personal
mics into the system, too. We calibrate EVERY ONE of these on a monthly
It is my exerience that , being first of all in good repair, being cleaned and
recalibrated monthly, and having been of good manufacture to begin with, there
is little PRACTICAL differencein the equipment. Added to this, there are many
Chinese and Japanese "knock-offs" in our system that, with the same care, will
produce equal result. When the ganefs were stealing all my new 0-1"
Brown&Sharpe and Starretts , I bought a dozen of the $12.95 0-1's from somebody,
Westport, MRO, Penn Tool, I'm not sure, They are a Chinese copy of the Mit's
with the BIG scales on the sides, read to tenths, also. And they ARE just as
reasonable and just as accurate and repeatable and reliable as the
But the single differentiating factor is (you guessed it) THE USER ! We have
some real craftsmen, genuine *machinists*, who will make accurate measurement
with any and all mics. Then, there are the "second-tier" individuals who
somehow, always manage to just get the part within sped - barely- unless the mic
has STARRETT on it. I don't know, just some sort of ego problem, a confidence
factor, who knows? Personally, I find an esthetic appeal it each different one.
Anyway, that's why GR&R is divided into GAGE REPEATABILITY (the equipment
factor) and GAGE REPRODUCIBILITY ( the operator factor).
We actually calibrate over 1,000 mics, (ID, OD, & depth) evry month, not to
mention about 150 lbs. of calipers, 80 lbs of small snap-gages, etc, ad