Validity of Calibration Stickers on Measuring Tapes and Rulers

Jim Wynne

Staff member
Admin
#11
When you are comparing the measuring tapes to the calibrated ruler, it would be very easy to have an accumulated error of anywhere between 1/64 to 1/32 depending on the graduations and length of the ruler and the graduations and length of the tape measure. A basic rule of thumb is the tool verifying an item for calibration be ten times more accurate than the dimension being calibrated, so you should be using calipers, calibrated to gauge blocks, to calibrate your jigs with .0625" tolerances (10 X .06 = .006).
In all cases, the simplest method that produces the desired results is what should be used.
 
Elsmar Forum Sponsor

Big Jim

Super Moderator
#12
Hi Team,

The Jigs we use have a calibration sticker on them indicating "Calibrated, ID#, By, Date and Due" We actually check these with a measuring tape and/or ruler to see if it's is in the specified tolerance. The question is, if the sticker says calibrated, is this politically correct?
Back here to the original question, you may want to obtain a copy of ISO 10012 for calibration guidance.

As others mentioned, the device used for either calibration or testing should be more accurate than the device being checked. Many use the 10:1 rule, partly because it is easy to move a decimal point. In many cases though, it is only 4:1.

So make sure the equipment is appropriate. A calibrated tape measure could easily be appropriate for checking your jigs, but a ruler to calibrate the tape measure may not be. You can buy calibrated tapes for around $40 to $45 so the expense of getting a properly calibrated tape really isn't much.

Make sure that the device has traceability to an international or national standard. If you calibrate it yourself, make sure your records show the device used and that the traceability trail is there.

On tape measures, as long as the tip isn't damaged and the numbers/lines are readable, a steel tape really does not go out of calibration. Buy a calibrated one, inspect it regularly, and replace it if the tip becomes damaged/bent or the numbers/lines become unreadable.

Calibrating tape measure has been a contentious topic here at the Cove, so I'm sure you will have many more comments about it.
 

Hershal

Metrologist-Auditor
Staff member
Super Moderator
#13
Hi Team,

The Jigs we use have a calibration sticker on them indicating "Calibrated, ID#, By, Date and Due" We actually check these with a measuring tape and/or ruler to see if it's is in the specified tolerance. The question is, if the sticker says calibrated, is this politically correct?
PC is irrelevant. If the tapes have been compared to a better item that is traceably calibrated AND the uncertainty of the calibration is included AND you have documented the traceability path, THEN the tape is calibrated.

Now, whether the tape is the correct item to measure the test fixtures (I am being PC here) is a different question. The test fixtures can be considered calibrated, but you need to have records that include the traceability path back to the tape, and include uncertainty.

Hope this helps.
 
I

Inunez

#14
Hi Team,

The Jigs we use have a calibration sticker on them indicating "Calibrated, ID#, By, Date and Due" We actually check these with a measuring tape and/or ruler to see if it's is in the specified tolerance. The question is, if the sticker says calibrated, is this politically correct?
i think his question is more about the word "calibration" being used on something you couldnt possibly adjust without ruining it somehow. i too have had my questions about whether Verified is a more adequate word in these situations...believe me my head still hurts!:frust:
but i'm learning that in this business it's not about the meaning of the word as much as it is about how it's been used, and calibrate is used to describe the act of verifying, adjusting, testing, etc.
believe me, its a losing argument lol :truce:
 

Jim Wynne

Staff member
Admin
#15
i think his question is more about the word "calibration" being used on something you couldnt possibly adjust without ruining it somehow. i too have had my questions about whether Verified is a more adequate word in these situations...believe me my head still hurts!:frust:
but i'm learning that in this business it's not about the meaning of the word as much as it is about how it's been used, and calibrate is used to describe the act of verifying, adjusting, testing, etc.
believe me, its a losing argument lol :truce:
It shouldn't be so difficult. To calibrate something is to compare it to a standard. Adjustment might not be necessary or even possible. There are different levels or types of calibration. In some cases, the comparison is all that's necessary. In others, records must be kept, uncertainty must be known, standards must be traceable, etc., etc. Some learned individuals will insist that the latter description is calibration, and the former is verification. What's important in the end is that everyone knows what everyone else is talking about.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#17
Generally speaking, the standard you use to calibrate a device should have a resolution 4:1 to 10:1 of the device resolution, as well as traceability to a national standard. So, for example, you would not use a steel rule to calibrate a micrometer.
 

Jim Wynne

Staff member
Admin
#18
Generally speaking, the standard you use to calibrate a device should have a resolution 4:1 to 10:1 of the device resolution, as well as traceability to a national standard. So, for example, you would not use a steel rule to calibrate a micrometer.
To avoid confusion and maintain control, classes or categories of devices should be created along with calibration requirements for each category. Steel rules, in general, shouldn't be subject to the same calibration requirements as micrometers, and CMMs need different treatment than pin gages.
 

Hershal

Metrologist-Auditor
Staff member
Super Moderator
#19
Hang on guys, before discussing stickers, the first question is why to have it calibrated. That is always the first question for some items. Somtimes there are good reasons and then cal it. But if no good reasons, then don't, and document why.
 

somashekar

Staff member
Super Moderator
#20
The industry we are in is wood. We are using a ruler which has been calibrated to certified calibration laboratory. The tape measures we use are checked against the calibrated ruler. The tolerance the product is ± 1/16th". Therefore the jigs also have to be to a tolerance ± 1/16".
The ruler or the tape by themselves do nothing to measure until they are used by competent persons and still a parallax error is possible.
So my basic question is to whom the validity is meaningful ?
If it is meaningful to both your customer and you, then you are well and safe.
What is the ware out on the jig as well as on the tape ?
I would suggest you use factory checked tape and replace periodically depending upon its use.
 
Last edited:
Thread starter Similar threads Forum Replies Date
U ISO 17025:2017 Clause 7.7 Ensuring the Validity of Calibration Results ISO 17025 related Discussions 6
M Validity of Calibration outside the Calibration Range General Measurement Device and Calibration Topics 7
S Validity of 7 Year Old Calibration Certificate General Measurement Device and Calibration Topics 19
D Validity of ISO 17025 calibration waivers due to proprietary procedures ISO 17025 related Discussions 4
E Validity of previous inspections when equipment is found out of calibration Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
lanley liao The validity of API Spec Q1 certificate Oil and Gas Industry Standards and Regulations 2
J Validity / outcomes measure for custom made medical device ISO 13485:2016 - Medical Device Quality Management Systems 2
F ISO 17025:2017 Clause 7.7 Ensuring the validity of results - Threshold ISO 17025 related Discussions 9
M Informational EU – Application of transitional provisions concerning validity of certificates issued in accordance to Directives 90/385/EEC and 93/42/EEC Medical Device and FDA Regulations and Standards News 2
D MDD Certification Validity after May 2020 EU Medical Device Regulations 12
E ISO 13485 7.6 Control of monitoring and measuring equipment - Assess the Validity ISO 13485:2016 - Medical Device Quality Management Systems 4
J ISO 17025 - Please share a sample procedure for monitoring the validity of results ISO 17025 related Discussions 1
T CE Certification Strategy - Expanding the validity of certificate EU Medical Device Regulations 1
M CE mark validity after Brexit, 29th March '19 EU Medical Device Regulations 6
M Is there an Industry Norm for Expiry of Sterilisation Validity? EU Medical Device Regulations 6
somashekar About NB suspension and CE certificate validity EU Medical Device Regulations 12
J EU CE Mark Validity in Non EU countries - Brazil. Taiwan, China, Japan, Mexico EU Medical Device Regulations 1
alonFAI ISO 9001 Quality Manual Validity Period ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 8
K Validity of Using NCR's to evaluate Performance Nonconformance and Corrective Action 7
G Validity for Thailand Medical Device License and can change Distributor thereafter? Other Medical Device Regulations World-Wide 3
G Validity of Extending Temperature Cycling Various Other Specifications, Standards, and related Requirements 3
D Assessing the Validity of Previous Measuring Results? General Measurement Device and Calibration Topics 8
C Validity of a 5 year ISO 13485 Certificate ISO 13485:2016 - Medical Device Quality Management Systems 3
A Validity of Internal Auditor Certificate/Training Quality Manager and Management Related Issues 14
A Expiration of Validity Date for EN ISO 14971 ISO 14971 - Medical Device Risk Management 8
A Validity of IEC 60601-1 and IEC 60601-2-27 - An intermittent ECG event recorder IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
rob73 Length of validity of a self certified Declaration of Conformity (DoC) for CE mark EU Medical Device Regulations 4
S Validity of "Ship to Control" - Do you endorse this approach? Statistical Analysis Tools, Techniques and SPC 16
C Validity Duration of USP / FDA Certificate? Other ISO and International Standards and European Regulations 5
V What is the Validity of IEC Test Reports? What about TRF Compliance? Other Medical Device Regulations World-Wide 2
J Length of Validity - Test Results Various Other Specifications, Standards, and related Requirements 2
K ISO 13485 Registration Certificate Life-Time (Validity Period) ISO 13485:2016 - Medical Device Quality Management Systems 21
Q Uncontrolled Hard Copy (Paper) Document Validity Period Document Control Systems, Procedures, Forms and Templates 12
J AS9100 Rev. B Certificate Validity AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 6
T CE Mark Validity despite expired 13485 Certification EU Medical Device Regulations 13
D IATF portal for TS 16949 Certificate Validity Check IATF 16949 - Automotive Quality Systems Standard 2
S Validity of Craig Hane's Global Local Index for X-bar R Chart Assessment Capability, Accuracy and Stability - Processes, Machines, etc. 3
P Validity of NB-MEDs (MDD / CE marking) EU Medical Device Regulations 2
M Validity of Old Biocompatibility Data (1999) - Catheter Other Medical Device and Orthopedic Related Topics 3
E Validity of ISO 9001:2000 Certificates - How to handle supplier ISO 9001 certificates ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 4
V Criteria used to assess the Validity of a Complaint - Insurance Company Customer Complaints 4
L How to check for validity of registration scope during ISO9001:2008 external audit Quality Manager and Management Related Issues 3
A Validity of ISO 9001 Certification ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 6
D Time frame for validity of ISO 9001:2000 Certifications IATF 16949 - Automotive Quality Systems Standard 3
C ISO 9001:2000 Certificate - How to have a 3 year validity instead of 1? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 15
C Ever come across an ISO 9001 certificate with more than 3 years validity period? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 35
E COA's (Certificate of Analysis) from suppliers - Beginning to question validity Supplier Quality Assurance and other Supplier Issues 4
P CE certificate validity - Signing employee has left the company EU Medical Device Regulations 7
M 7.6 - Validity of the previous measuring results - Is this what validity means? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 5
T Variables Gage R&R - Minitab v14 - F statistic Calculation - ANOVA - Methods validity Using Minitab Software 2

Similar threads

Top Bottom