Thread Plug Gage Pitch GO Diameter out of spec

[vinaysp225]

Hi,Dear All
please help me on this below issue

Recently i sent thread plug gauge for calibration .
after receiving the calibration report its go side pitch diameter out of spec.

M1.7*.35-6H
GO Pitch diameter-1.479±0.0045( Actual: 1.4847)
NOGO PITCH diameter-1.5625±0.0045 (Actual : 1.5703)

GO SIDE OVERSIZE BY 1 MICRON
NOGO SIDE OVERSIZE BY 3 MICRONS.

Please suggests your opinion can i use this gauge further or i want to scrap the gauge.
we have around more than 20 gauges in out of tolerances conditions.

Regards
vinay

 

[Johnny Quality]

vinay,

To paraphrase Dr Deming; how should you clean a table? Context is needed - what do you use the gauges for?

 

[vinaysp225]

vinay,

To paraphrase Dr Deming; how should you clean a table? Context is needed - what do you use the gauges for?

We use this gauge to measure the metal stamping part

 

[Miner]

A calibration service is required to report the results of calibration using the tolerances of the class of gage. However, there is nothing that requires you to use the same tolerances. Look at your application, and determine the tolerances required by that application. What gage tolerances are required to accurately and precisely measure to those tolerances? Those are the gage tolerances that you can use for your internal use. If these are more relaxed than the gage class tolerances, you will need to document your rationale and your analysis, but you may then accept the gage.

I have used this approach before when someone ordered a gage set of a higher class than was necessary for our application.

 

[outdoorsNW]

Is the gage a general purpose gage or is it dedicated to a single purpose?
If it is a dedicated single purpose, can you guard band the tolerance so you will never pass non conforming product?
If everything is well documented and the gage is marked somehow so people know not to trust it for other uses,, this would be acceptable to most customers.

 

[Johnny Quality]

If the gauge is used only for one part the next question I'd ask is if the gauge is used would it reject conforming parts or accept non conforming parts. This may be a reason to why you have "around more than 20 gauges in out of tolerances conditions".

 

[dwperron]

Oversize thread gauges can produce false pass or false fail results. You need to determine what the risk is to your products.
You say you have 20 out of tolerance gauges. Depending on the circumstances involved, my spider senses would be tingling.
If this is the first time the gauges have been calibrated you have no history to fall back on. If you have calibrated them in the past (and I assume they were found in tolerance) you can look for trends. Undersized gauges could simply reflect wear. Oversized gauges could indicate tools made from inadequate quality steel that have "relaxed" and expanded. Also you only mention the pitch diameter. Oversize gauges should also fail the Major diameter test, did they check that?
If 20 out of 2000 gauges were out of tolerance then that feels OK. 20 out of 50.... I would be worried about my calibration provider.
I myself would be looking to get a second opinion from another lab on a couple of test samples in either case.
It all depends on whether you have history on the gauges to review. Without the history it is harder to determine what happened.

 

[vinaysp225]

owever, there is nothing that requires you to use the same tolerances. Look at your application, and determine the tolerances r

A calibration service is required to report the results of calibration using the tolerances of the class of gage. However, there is nothing that requires you to use the same tolerances. Look at your application, and determine the tolerances required by that application. What gage tolerances are required to accurately and precisely measure to those tolerances? Those are the gage tolerances that you can use for your internal use. If these are more relaxed than the gage class tolerances, you will need to document your rationale and your analysis, but you may then accept the gage.

I have used this approach before when someone ordered a gage set of a higher class than was necessary for our application.

Hi
Thank you for your feedback.
i will do the same

 

[vinaysp225]

Oversize thread gauges can produce false pass or false fail results. You need to determine what the risk is to your products.
You say you have 20 out of tolerance gauges. Depending on the circumstances involved, my spider senses would be tingling.
If this is the first time the gauges have been calibrated you have no history to fall back on. If you have calibrated them in the past (and I assume they were found in tolerance) you can look for trends. Undersized gauges could simply reflect wear. Oversized gauges could indicate tools made from inadequate quality steel that have "relaxed" and expanded. Also you only mention the pitch diameter. Oversize gauges should also fail the Major diameter test, did they check that?
If 20 out of 2000 gauges were out of tolerance then that feels OK. 20 out of 50.... I would be worried about my calibration provider.
I myself would be looking to get a second opinion from another lab on a couple of test samples in either case.
It all depends on whether you have history on the gauges to review. Without the history it is harder to determine what happened.

Hi
Thank you very much for you great help.

1.All these gauges we purchased last year due its conditions was new we used as it is by verifying the manufacturer certificate.
but this year i sent those thread plug gauges for calibration after reviewing the calibration results its GO & NOGO pitch dimater out of specification as per JIS B 0251 standard.

2.Major diameter was well with in specifications.

3.As you said , we will give few samples of thread plug gauge to other calibrating agency for clarification &will decide.