Downgrading Ring & Plug Gages After Failed Verification (ISO 9001 Implications)

[Thumper]

I’m looking for clarification on how to properly handle ring/plug gages that fail verification for their marked class, but still meet the requirements for a lower class.

In our situation, a ring gage failed calibration for the class stamped on the tool. The calibration certificate is marked as failed for Class XX. The measurement data shows the gage would meet Class X limits. Both Class XX and Class X exceed our internal tolerance requirements.

We’re considering downgrading the gage from Class XX to Class X instead of scrapping it.

Since the certificate already contains the measurement data demonstrating that the gage meets Class X limits, can we rely on that existing certificate and update our log to reflect a Class X designation, even though the certificate shows a fail for Class XX?

Or, do we need to send the gage back for a new calibration performed specifically to Class X so that the certificate cleanly reflects the new class, with no failure listed?

I want to ensure our approach is ISO 9001 compliant and avoids traceability concerns during an audit.

Has anyone dealt with this before, and how did you handle the documentation?

Thanks in advance for your insight!

 

[DietCokeofEvil]

I can't speak for all labs, but we see this quite often. It would be up to your engineering department, or quality department to verify that downgrading the ring would not affect your processes at all.

If they don't, I highly recommend that you reach out to your calibration house. There are a few options:

1. Resize the ring to fit XX tolerance. (This is a tough one because it's pretty tight, but never hurts to check)
2. Request the cert to be reclassified to whichever tolerance you request. Our lab would do this and provide a supplementary note regarding the change to the cert and why.

For my lab, it's just a matter of re-entering the ring and then the software does the rest and the cert is in tolerance- but regardless of how a lab does it, they should be able to change the class and not re-measure the ring.

I don't recommend changing it in-house and not informing the lab, because when you send it in again, you'll be in the same boat if the lab doesn't know you reclassified, even if you re-mark the ring.

 

[dwperron]

I’m looking for clarification on how to properly handle ring/plug gages that fail verification for their marked class, but still meet the requirements for a lower class.

In our situation, a ring gage failed calibration for the class stamped on the tool. The calibration certificate is marked as failed for Class XX. The measurement data shows the gage would meet Class X limits. Both Class XX and Class X exceed our internal tolerance requirements.

We’re considering downgrading the gage from Class XX to Class X instead of scrapping it.

Since the certificate already contains the measurement data demonstrating that the gage meets Class X limits, can we rely on that existing certificate and update our log to reflect a Class X designation, even though the certificate shows a fail for Class XX?

Or, do we need to send the gage back for a new calibration performed specifically to Class X so that the certificate cleanly reflects the new class, with no failure listed?

I want to ensure our approach is ISO 9001 compliant and avoids traceability concerns during an audit.

Has anyone dealt with this before, and how did you handle the documentation?

Thanks in advance for your insight!

You can certainly downgrade the accuracy of a ring or plug. It happens all the time. Document the new accuracy class in your records so there are no questions. You don't need your calibration vendor to do anything except provide the data, you can change the accuracy class to what is appropriate for your needs.
Something you should be aware of is that some tools will have a tendency to "grow" as they age. If you see that your gauges are changing with time it is probably time to retire them.