Articles by Hill Cox

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?

We’ve all heard it before. Someone says, “If you want my opinion...” and they give it to you even after you’ve told them you don’t want it.

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.

I mention this term upfront to save irate letters from purists who decry the use of slang terminology due to problems it can create.

Every industry has a jargon of its own and dimensional metrology is no different. The reason is ease of verbal communication, but that communication can be confusing at times for the uninitiated.