Too often users of precision measuring instruments and gages end up with the wrong equipment and don’t find out until it’s too late. ‘Too late’ means after rejects are detected by in-house measurements or in worst case scenarios, by their customer.
In an age where, if it doesn’t have a digital display it’s not modern, we tend to forget how the levels of precision we measure to came about in the first place. This is a brief look at one of the people we are indebted to for their discoveries and inventions from many years ago.
Anyone in the fastener or screw machine business producing screw threads is familiar with ‘pitch’ micrometers. These relatively simple devices are often used to set up production equipment and monitor their output, but there are many misconceptions about them which can call their usefulness into question.
Gage manufacturers and calibration laboratories often find themselves in this minefield. New gages or instruments are supplied or calibrated and immediately returned by the customer because they aren’t correct.
A reader asked me to comment on a situation he faced regarding calibration frequency for some gages he had on loan from his customer. The gages are only used once a year for this specific customer and—I’m guessing—spend about 80% or more of the year doing nothing.
A reader emailed me after reading some of my rants on thread ring gages dealing with the problems that come up in their use and calibration. But he added another dimension to the problem since he is in the calibration business: How do the Europeans deal with their solid thread ring gages?
The term ‘proficiency testing’ is one that every accredited calibration laboratory is quite familiar with. In basic terms it refers to a method of evaluating how well a laboratory is doing a particular calibration with respect to its claimed measurement uncertainty and how it fares with other participants.
If you’re having problems with thread measurements but the answers you’re getting from your usual sources aren’t solving them, it’s natural that you would try and get some unbiased advice from a specialist.