The problems encountered with screw threads are legendary. The most common one occurs when the gages do what they are supposed to do: reject bad parts or accept good parts.
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.
Whenever there’s an economic downturn two things happen: more measuring instruments get repaired when they should be replaced, and more people start going to auction sales looking for bargains.
In a previous column I railed against corporate cost cutting strategies where the only element taken into consideration was the money involved. The fallout from decisions made in such isolated circumstances will not be immediately evident, while the savings will be. But when the chickens come home to roost, the costs to put things right often exceed the savings many times over.
One of the good things about getting items calibrated is the information the process provides. The bad news is some folks don’t know how to deal with that information. Far too many buyers of calibration services only scan the reports and, in the absence of red flags, file them in case an auditor wants proof of calibration.
I’m surprised at some of the ideas that drift down from the loftier realms of the corporate world in the endless quest to reduce costs. In many cases, the assumption is that a philosophy that appears to work in one area of a company’s operations can be applied to all areas.
There are two approaches to take regarding temperature changes and the effects they have on measurement. The first is to control the shop or lab environment to such an extent that, whatever temperature variations remain, they will have no significant effect. The alternative is to control and correct the key items involved-the gages and the product being measured. The simplest method for most folks is to control and correct.