What is the "correct" frequency for checking the calibration of gage blocks (grade 2) used as masters for other gages? Assume that they are not used for anything else, and are stored in a lab environment.

Is there a standard regarding this?

Thanks for your help,

Norman V.

What is the "correct" frequency for checking the calibration of gage blocks (grade 2) used as masters for other gages? Assume that they are not used for anything else, and are stored in a lab environment.

Is there a standard regarding this?

Thanks for your help,

Norman V.

As far as I know there is no standard. Calibration frequency should be based on experience, in general. Make a predicition: "We should need to calibrate master blocks no more often than X." Then test your hypothesis. Use an accredited calibration lab, and pay attention to the "as-found" condition of the blocks, then do the calibration again after a period of X, again making note of the as-found condition. The results will provide objective evidence of the efficacy of your prediction.

Jim is correct. It goes for other gauges too.

wallyqc

Norman,

I agree with the other posts. An analysis of your data after routine calibration should yield if you are having expansion/contraction, which may need to be monitored. Otherwise, any calibration interval, outside of regulatory requirements, is yours to set as is necessary.

I suggest looking at NCSLI Recommended Practices (RPs), I believe RP-1 is the correct one.....

Talk to your (hopefully) accredited calibration provider and get their input.....

Then look at the data.....I would say a maximum of 36 months, though 12 months is a more typical starting point.

Hope this helps.

Hershal

Thanks to everyone who replied! :thanx:

My main concern was that there was not an existing standard that "required" a specific frequency. Following Hershal's advice, I'll also look into the NCSLI RP.

Based on my calibration wear history, I have backed off our frequency to every 2 years, and we'll see how it goes from there.

Norman V.

What is the "correct" frequency for checking the calibration of gage blocks (grade 2) used as masters for other gages? Assume that they are not used for anything else, and are stored in a lab environment.

Is there a standard regarding this?

Thanks for your help,

Norman V.


I agree with Hershal and Jim Wynne. Most of my clients do a 2-3 yr calibration for their "master" set of blocks (limited use, never leaves the lab, etc.). As long as there is no visible wear or damage to the blocks, there should be little change.

Two exceptions I see:

Some clients follow a one year because their lab has fairly inexpensive rates.

If your products are high precision, low tolerance, maybe more frequent would be better, because the margin of error is so much tighter.