- THE MAGAZINE
- WEB EXCLUSIVES
Does new stuff have to be calibrated? The short answer to the question is “yes,” so you don’t have to read further unless you want to know why.
The technical term “new stuff” refers to new, unused gages and instruments. The main question leads to another thought. If the stuff is new, it has to be good or suppliers wouldn’t ship it-would they? This comment suggests that the supplier actually checked your stuff before shipping, which is not always the case. It also assumes that the reliability of this inspection is good, which is not always the case either.
Many makers of gages and measuring instruments include a piece of paper with each item which claims the items have been inspected. But the value collapses when the same piece of paper says that if the buyer finds the instruments to be incorrect, the supplier’s liability is limited to repair or replacement of the defective item. Being linguistically challenged, I assume that if the items have been calibrated by their “highly skilled technicians,’’ there won’t be anything wrong with them. But, alas, my assumption is incorrect.
Too many people accept these bits of paper as if they were as good as a calibration report. The fact that they don’t cost the buyer anything indicates what they are worth. So the answer to our primary question is followed by another question: What is going on here anyway?
The answer to that question is: Not what you’d think.
In a perfect world, finished gages must pass final calibration by someone other than the person who made them. This provides independent confirmation that the gages meet specifications. In our world, this is becoming an exception rather than the rule it used to be.
Cost cutting is the reason this important final check is being omitted by many gage makers. And, this is done to try and meet the never-ending demands for lower prices by those gage users who consider a gage as little more than another lump of steel.
If the gage maker, or their sales agent, doesn’t provide this check, the gage user is left to discover mistakes or errors the hard way. When this occurs, price is no longer the overriding preoccupation of the buyer. Smart gage buyers get new gages checked by their own laboratory or a competent outside facility to avoid these problems, or they pay for a proper calibration report from the gage maker.
Accounting 101 will explain that savings on the purchase price will be offset by the cost of “final” calibration, if accuracy is to be ensured.
New measuring instruments are frequently used out of the box, usually with few problems, but when problems arise, they can be just as expensive as fixed limit gages.
Setting masters supplied with the instrument often are found not to be as advertised, which can create mayhem for all. Since many instruments are made off-shore by unknown companies, you can never be certain what you’re getting, irrespective of what brand name they carry in this market. While some makers shouldn’t be in business, most problems arise because the maker is producing instruments to the standards of a different country, and the American importer either doesn’t know this or does but simply neglects to pass this information along. Often the foreign standard allows errors that are much higher than what the equivalent U.S. standard permits. There is nothing wrong with this, providing the buyer is aware of the situation. Usually they are not.
Interchangeable anvils, rods and other devices may have settings that are incorrect and will never be found until the instruments are calibrated. Distributors may have mixed up these items from one set with those of another without realizing the implications of doing so.
Similar problems arise with lever-type test indicators when contact points from one model are mixed up with those belonging to another model.
While the electronics on popular instruments are of a high standard today, not all of them are. Occasionally intermittent defects occur and may cause a lot of rejects until they are found.
The only way to avoid having these troublesome situations is to know that every gage or instrument entering your operations is good on the way in. And the only way to know that is to confirm it through calibration.