Dial Indicator Calibration Frequency - ASME/ANSI B89.1.10M-1987

[gagegirlvenus]

In ASME/ANSI B89.1.10M there is no reference to a recommended, min or max calibration frequency. Some standards state a maximun allowable frequency. I set the frequency for dial indicators at 1 year (annually). Does it matter if an indicator is calibrated in February and set the next due date to say October of the next year? I have reviewed the calibration history (no failures) and reviewed the graph for each test point showing no major drift in either direction. Is this acceptable?

[Jim Wynne]

In Reply to Parent Post by gagegirlvenus

In ASME/ANSI B89.1.10M there is no reference to a recommended, min or max calibration frequency. Some standards state a maximun allowable frequency. I set the frequency for dial indicators at 1 year (annually). Does it matter if an indicator is calibrated in February and set the next due date to say October of the next year? I have reviewed the calibration history (no failures) and reviewed the graph for each test point showing no major drift in either direction. Is this acceptable?

Calibration intervals should be set based on risk and history. You're doing that, it appears.

[gagegirlvenus]

Just wanted to confirm I was on the right path. Thanks!

[Ninja]

You may be doing this already, but I don't see it written above...

Many dial indicators fail catastrophically (ie. an internal part like a spring breaks). If your usage or your gage may be prone to this as mine are, you might consider having a step before usage against knowns.

For me, I keep a known (calibrated) 75um piece right with the gage. When going to use the gage, it is zeroed first, then the 75um known is measured, then off we go.
It takes an extra 3 seconds, but has caught two gages now that had broken internally. Both had ~6mnths left before being due for recalibration.

Since the 'known' has very little risk of changing (dropping it on the floor and stamping on it wouldn't change it), it is on a much longer calibration cycle.

HTH

[gagegirlvenus]

I have not seen this issue with most of the 2900 dial indicators we have. These indicators are used on bar gages and set or verified between my calibrations with "known" set masters and reconfirmed on an 80" Trimos by the gage setters. The gage setters will ususally catch any issues with the dial indicators at setting. I will keep your idea in mind going forward. TY!!!