Some gage users would be quite pleased to have gages that keep growing in size to negate wear. Unfortunately, it’s not a controllable situation and will result in your no-go plug gages going oversize on a continuous basis. You win some, you lose some.
With so many gage buyers focusing on costs alone rather than what they are actually getting for their dollars, it follows that suppliers will do the same. It often becomes a situation where a gage buyer pretends to want calibration while the supplier pretends to deliver it.
I recently received an e-mail from a faithful reader who had a problem regarding the calibration of adjustable thread ring gages. He realized that the rings should be verified using calibrated thread setting plugs, but he didn’t have enough of them to cover all of his rings. His company had avoided buying setting plugs in the past, so he doubted they would do so now.
I still get asked questions that were answered many times years ago and wondered why this could be. The answer is simple: Years ago, the people involved in calibration or product inspection got their jobs after serving time as machinists and toolmakers. Today, people are plugged into these areas without the same kind of experience so they’re starting from square one.
The last time I checked, most folks have gages calibrated to determine what sort of dimensional state they are in. A properly presented calibration report will tell you if there is a possibility that some bad work was shipped because of a worn gage. Now, I know that wouldn’t happen at your company, but it does at some. Alternatively, the information provided could be a warning that this could happen in the not-too-distant future.
I stand in awe of the lowly screw thread because of the engineering that goes into it. A cursory look at a typical screw thread standard will show you what I mean. Despite their innocent appearance, screw threads are difficult to measure.