For Reference Only or Calibration/Verification - Tape Measures for cutting bar stock

[dtr18c]

I got this from Calibration of Tape Measures

Are the tapes used to "determine acceptance of the product" for movement to the next function area or for shipment?
If not, label them as "reference tools" (assuming that you have some other method of measuring/testing the product for conformance to specification. If they are, I believe that you may be in a pinch. Tape measures are subject to so much regular abuse, malformation, and other circumstances that would impact their accuracy (to some tolerances) --> you might find yourself hard pressed to keep them calibrated (or spend a ton of time rechecking them).

We cut barstock into lengths +/-0.5" for lathe operations with automatic bar feeders. This cut length doesn't affect final product characteristics. I'm unsure of having our tapes say reference only or having tape calibration/verification requirements. Thoughts?

Thanks.

[db]

Go back to the standard. Are the tapes used in a manner that requires valid results? If so, then 7.6 applies. Checking tape measures is actually quite easy. Have a fixture calibrated at a given lenght. Then each time employees clock in, have them check their tapes against the fixture. One of my clients has a bar that has an 11" scribe mark. This mark is verified every other year. It is attached to a wall. When the operators verify their tapes, the acceptance criteria is that if any part of the scribe touches any part of the 11" mark on the tape, it is considered to be acceptable.

I strongly advise against having gages (or documents) "For Reference Only"

[AndyN]

In Reply to Parent Post by db

Go back to the standard. Are the tapes used in a manner that requires valid results? If so, then 7.6 applies. Checking tape measures is actually quite easy. Have a fixture calibrated at a given lenght. Then each time employees clock in, have them check their tapes against the fixture. One of my clients has a bar that has an 11" scribe mark. This mark is verified every other year. It is attached to a wall. When the operators verify their tapes, the acceptance criteria is that if any part of the scribe touches any part of the 11" mark on the tape, it is considered to be acceptable.

I strongly advise against having gages (or documents) "For Reference Only"

Well said, Dave!

[ab001]

If you can't trust your tape to give you a one inch range, there's probably bigger problems with the tape - trust one that's still in the packet.

if there's a problem with the stock length - focus on the auto feeder instead of the tape measures

In Reply to Parent Post by dtr18c

I got this from Calibration of Tape Measures


We cut barstock into lengths +/-0.5" for lathe operations with automatic bar feeders. This cut length doesn't affect final product characteristics. I'm unsure of having our tapes say reference only or having tape calibration/verification requirements. Thoughts?

Thanks.

[BradM]

In Reply to Parent Post by db

Go back to the standard. Are the tapes used in a manner that requires valid results? If so, then 7.6 applies. Checking tape measures is actually quite easy. Have a fixture calibrated at a given lenght. Then each time employees clock in, have them check their tapes against the fixture. One of my clients has a bar that has an 11" scribe mark. This mark is verified every other year. It is attached to a wall. When the operators verify their tapes, the acceptance criteria is that if any part of the scribe touches any part of the 11" mark on the tape, it is considered to be acceptable.

In Reply to Parent Post by db

I strongly advise against having gages (or documents) "For Reference Only"

I concur about not having For Reference Only on instruments, if all the instruments in the facility are verified. If you have some that are verified and some that are not, there needs to be a means of segregation. Adequate labeling can serve that purpose.

[DrM2u]

In Reply to Parent Post by dtr18c

I got this from Calibration of Tape Measures


We cut barstock into lengths +/-0.5" for lathe operations with automatic bar feeders. This cut length doesn't affect final product characteristics. I'm unsure of having our tapes say reference only or having tape calibration/verification requirements. Thoughts?

Thanks.

Here's my worth:

It is up to you to define the calibration interval for inspection equipment but keep in mind that the frequency must be adequate to ensure equipment's suitability and reliability (or something along these lines). You can state (verbaly or in writing) that measuring tapes are purchased certified (not calibrated) by the manufacturer (and some OEMs like Starrett do certify them) and used until they are damaged, after which they are replaced. The responsibility for assessing the state of a tape and requesting a replacement could/should be delegated to the user. However you would need to keep records of when the tapes were placed in and removed from service (and a certification document from the OEM for any tape in use) to evidence the verification of the equipment.

Let's use some common sense on this. You are talking about 1/2" tolerance on them bars. What is the impact of the bars being shorter by more than 1/2"? You lose enought material for a part?!? What is the value of a part (or a few more until you detect the problem) and can you financially justify an expansive and expensive calibration system for tapes? Or what is the impact of the bar being longer that 1/2 "? It cannot be more than 1" because that would imply that the tape's bar/hook/tongue is bent straight or broken, which renderd the tape unusable. You can use my argument to challenge any auditor who would write a finding on this. What is the value they are bringing to the audit process?!?

[Helmut Jilling]

In Reply to Parent Post by DrM2u

Here's my worth:

...Let's use some common sense on this. ...What is the value of a part (or a few more until you detect the problem) ..and can you financially justify an expansive and expensive calibration system for tapes? ...You can use my argument to challenge any auditor who would write a finding on this. What is the value they are bringing to the audit process?!?

Why does it have to be expensive at all? Buy a $10 tape measure, verify it once (against a calibrated 36" master steel rule) before use to make sure it is correct. Then, periodically determine the condition is still good. I agree this is not NASA and does not have to be complicated. But, it can be done so easily... And the same principles can be applied to many other gages...THAT is the value that an auditor can "bring to the audit process..."

[John Martinez]

In Reply to Parent Post by db

Go back to the standard. Are the tapes used in a manner that requires valid results? If so, then 7.6 applies. Checking tape measures is actually quite easy. Have a fixture calibrated at a given lenght. Then each time employees clock in, have them check their tapes against the fixture. One of my clients has a bar that has an 11" scribe mark. This mark is verified every other year. It is attached to a wall. When the operators verify their tapes, the acceptance criteria is that if any part of the scribe touches any part of the 11" mark on the tape, it is considered to be acceptable.

I strongly advise against having gages (or documents) "For Reference Only"

I'd like to see the term "for reference only" removed from the quality profession.