Requirements for In-House calibration of measuring devices.

[dwperron]

After further research I think I would be fine with just verification of our measuring devices. I will use certified blocks to verify our equipment. Now I need to put together what our procedures would be. Do you have any idea where I might find a guide for what the procedures should look like?

Here is an organization that publishes some good calibration procedures:
Calibration Guidelines

 

[hogheavenfarm]

I actually provide a graph of the results of our calipers, along with a sheet showing the measurements taken and the results. In this way there is verification and a means of adjustment (since you can look at the graph and see at what point the caliper is "out" and by how much.)

 

[Miner]

I actually provide a graph of the results of our calipers, along with a sheet showing the measurements taken and the results. In this way there is verification and a means of adjustment (since you can look at the graph and see at what point the caliper is "out" and by how much.)
View attachment 31168

You could enhance this with two lines, a Before and an After line.

 

[hogheavenfarm]

Yes, I do that in the (separate) written report, this is simply a graphic for the user of the device to know what it is capable of.

 

[greif]

1) Verification is calibration per the International Vocabulary of Metrology.
(Calibration is comparing to a known standard, no adjustment required)

https://www.bipm.org/documents/20126/54295284/VIM4_CD_210111c.pdf

2) Here are some basic cal procedures;

Quality 101:Calibrating Micrometers

Regular calibration intervals help ensure micrometer accuracy.

www.qualitymag.com

There are Mil Std procedures for calibration of hand tools (I remember Navy ones in particular) but I am not finding them in a quick search.

For our internal use we do the following for micrometers:
Take 3 zero readings and check repeatability.
Position a thin gage block near the edge of the anvil at 0,90,180, 270 degrees with readings at each to check anvil parallelism.
Take 8 gage block readings , spanning the length of measurement, and covering ~ 1/4 turn x4 position of the thimble.
For digital; take at least 1 reading in MM (if all other readings were English) to verify conversion is correct.

You can do a lot more tests, but you must determine you own risk tolerance.

 

[Steve Weber]

Our company is similar to what Scanton wrote. We have a set of Ceramic Gage Blocks, along with Length Standards, Pitch Mic Standards, Bore Rings and Surface Finish Masters. We send them all to an outside supplier that is 17025 Certified. Each item gets a Calibration Certificate. We use these to calibrate the gages in house both company and employee owned. Every gage is logged into our database where we enter the results of the calibrations. We have been ISO9001 / AS9100 Certified since 2004 and have had no issues using this method. We do send Thread Plugs & Thread Rings out for calibration to the same supplier that does the items listed above. Works for us!