Measurement disputes over gage calibration continue despite the results of the studies noted in my previous column. As Jim Popovic, AMTMA’s managing director, put it when we were reviewing the results: “We still have people knocking their brains out over differences in readings of a few millionths of an inch. And we still have labs who believe their uncertainty for such measurements is “...a few millionths.”
Those who believe their capabilities are much better than noted in the previous column try to explain variations away by suggesting a slight difference in where the measurements are taken on the gage could cause a significant difference in the readings obtained, which is true. However, this possibility was foreseen and the gages were marked and a sketch provided to show where the measurements were to be taken. This procedure has been followed for all of the studies referred to.