Calibrating or Verifying Metal or Steel Tape Measures

Re: Calibrating Tape Measures

bobdoering said:

So, sure, if you are a minimalist you will not see the sense in that...but somebody did...and there it is. If you quality system is TCE and not ISO/TS 16949, then you are pretty much free to do whatever you can "justify".

Click to expand...

I don't see that TS 16949 is any more inclusive of equipment than ISO 9001.

bobdoering said:

... all gauges, measuring and test equipment, needed to provide evidence of conformity...

Click to expand...

How is that different from this?

ISO 9001 said:

Where necessary to ensure valid results, measuring equipment shall...

Click to expand...

Both say if it's needed, you must address it. If it's not needed, you can decide.

Re: Calibrating Tape Measures

bobdoering said:

Yes, there is the fun part. Let the games begin. If it wasn't for this, we wouldn't need screen printed pocket scales or trade show plastic calipers.

Now, if you step out of ISO 9001:2008 quality level TCE and step into ISO/TS 16949:2009, the criteria is a little more specific:

7.6.2 Calibration/verification records
Records of the calibration/verification activity for all gauges, measuring and test equipment, needed to provide evidence of conformity of product to determined requirements...

So, sure, if you are a minimalist you will not see the sense in that...but somebody did...and there it is. If you quality system is TCE and not ISO/TS 16949, then you are pretty much free to do whatever you can "justify".

Click to expand...

What you blithely ignore or misunderstand in the 16949 citation is the word "verification"; the requirement is different from the ISO 9001 requirement mainly in the mandate for records of verification. In other words, if I use a tape measure for some inspection task that provides evidence of conformity of product, the tape must be somehow verified and a record must be retained of the verification.

Thus if I buy a tape measure and upon receiving it I verify that it's suitable to the task (using whatever criteria I determine to be appropriate) and record that activity, I've satisfied the 16949 requirement without actually calibrating anything.

I used to work in a precious-metal plating shop. One of the things we had to do for some customers was an electrographic porosity test. This involves clamping a sample between two pieces of photosensitive paper and applying electrical current for x minutes. Then the paper was put in a developing solution for y seconds, all of this according to explicit customer requirements. The timing devices were a common kitchen timer and the second hand on the wall clock, neither of which were ever even verified, let alone calibrated. Amazingly, this testing went on for years and may still be going on today without any issues that could be traced to measurement error or lack of calibration.

I can provide many more examples.

What, when and how to calibrate things is most of all a matter of rational informed judgment. If there is fear of allowing people to make rational judgments, or more to the point, fear that they might be incapable of rational judgment or not trustworthy, there's a bigger problem at hand than calibration.

Re: Calibrating Tape Measures

howste said:

Both say if it's needed, you must address it. If it's not needed, you can decide.

Click to expand...

If you look at the converse:

Records of the calibration/verification activity for all gages, measuring and test equipment, not needed to provide evidence of conformity of product to determined requirements...
then you can see that tape measures used for plant layout or temperature controllers used for the water cooler really do not fall into the category of needing to provide evidence of conformity of product to determined requirements.

But, of course, I am not the ultimate referee for this question - it falls between you, your customers and your assessor. If the three of you agree on the interpretation is "if you bought it, it has to be good" or some other "you decide" approach that requires not further comparison to a standard (verification or calibration...although apparently there is debate about those terms too. It appears to some verification means you got a receipt with your gage purchase), then you can go on you way to defect-free manufacturing.

WOW, Tape measures are evil... LOl
We will be going to a different procedure the first of the year. Instead of calibrating our tapes to steel rules we would like to buy a brand of tapes & get a manufactuere tolerance certificate for their tapes. I'm having issues though writing a plicy or procedure on this. Would anyone be willing to give me soe advice? :truce:
Thanks.

KyleB said:

WOW, Tape measures are evil... LOl
We will be going to a different procedure the first of the year. Instead of calibrating our tapes to steel rules we would like to buy a brand of tapes & get a manufactuere tolerance certificate for their tapes. I'm having issues though writing a plicy or procedure on this. Would anyone be willing to give me soe advice? :truce:
Thanks.

Click to expand...

Buying certified tapes is significantly more expensive. Assuming your needs are not critical, it is a simple matter to verify tapes against a master steel rule. If you want to go that route, however, putting in your exosting procedure should be simple. Just indicate that buying manufaturer certified gages is an acceptable option. (Note, to qualify in TS-16949, the manufacturer must be accredited to TS-16949).

Re: Calibrating Tape Measures

bobdoering said:

If you look at the converse:

Records of the calibration/verification activity for all gages, measuring and test equipment, not needed to provide evidence of conformity of product to determined requirements...
then you can see that tape measures used for plant layout or temperature controllers used for the water cooler really do not fall into the category of needing to provide evidence of conformity of product to determined requirements.

But, of course, I am not the ultimate referee for this question - it falls between you, your customers and your assessor. If the three of you agree on the interpretation is "if you bought it, it has to be good" or some other "you decide" approach that requires not further comparison to a standard (verification or calibration...although apparently there is debate about those terms too. It appears to some verification means you got a receipt with your gage purchase), then you can go on you way to defect-free manufacturing.

Click to expand...

I think it should depend on what the standard says. I am tired of assuming clients in their next audits and see thngs that are off, and be told the previous assessor said it was "ok." PS: I don't get too nervous about the maintenance guy's tape measure.

If you find one that sells them with certs, please let me know all I ever got was verbal gurantees within 1/16.
thanks

Riverbend said:

If you find one that sells them with certs, please let me know all I ever got was verbal gurantees within 1/16.
thanks

Click to expand...

And, there is a difference between what I would classify as a certificate of calibration, and... other certificates.

A decent calibration certificate is where someone tested the specific device that you purchased, at a very current date, using standards and such, and assessing it against a tolerance requirement.

Other certificates may list some conformance to something, or where a particular lot was tested, etc.

The legitimate calibration certificate is highly valuable to me. The second "other" certificate has never really been useful that I could tell.

I have never really seen a "calibtare-able" tape measure anyway, all you could would be to bend the end catch one way or the other. I have never had so much as an obseversation in any of the 8-10 audits I get each year over the way we "verify" tales on calibrated steel rules.
All you are basically doing is comparing painted lines against machined or other painted lines anyway. A simple tape, unless it is a PI tape isn't accurate enough for a low toleranced dimension anyway, can u say Roamer CMM. or Laser measuring device, mucho $$$.

Riverbend said:

I have never really seen a "calibtare-able" tape measure anyway, all you could would be to bend the end catch one way or the other. I have never had so much as an obseversation in any of the 8-10 audits I get each year over the way we "verify" tales on calibrated steel rules.
All you are basically doing is comparing painted lines against machined or other painted lines anyway. A simple tape, unless it is a PI tape isn't accurate enough for a low toleranced dimension anyway, can u say Roamer CMM. or Laser measuring device, mucho $$$.

Click to expand...

Calibration is comparison to a standard, and doesn't necessarily imply adjustment or the ability to adjust.