Calibration of 200 sets of Thread Ring Gages - Return them to the manufacturer?

[Grizz1345]

I am looking for feedback on how people approach the calibration of thread ring gages. My experience has been to return them to the manufacturer. I am really looking for a faster and more economical approach. I have approximately 200 sets of thread ring gages in my database. All comments would be appreciated.

 

[D.Scott]

I am looking for feedback on how people approach the calibration of thread ring gages. My experience has been to return them to the manufacturer. I am really looking for a faster and more economical approach. I have approximately 200 sets of thread ring gages in my database. All comments would be appreciated.

We return our ring gages for calibration. Our schedule rotates the sets so we are never without calibrated sets.

I suppose, depending on the criticality if the measurement, you could verify the gages in-house. Buy a master set of calibrated plug gages and verify the ring gages internally. That way you would only need to send out the master for calibration. 200 sets may be pushing the limits of the master set though so you may have to calibrate it more often.

Dave

 

[Crusader]

We return our ring gages for calibration. Our schedule rotates the sets so we are never without calibrated sets.

I suppose, depending on the criticality if the measurement, you could verify the gages in-house. Buy a master set of calibrated plug gages and verify the ring gages internally. That way you would only need to send out the master for calibration. 200 sets may be pushing the limits of the master set though so you may have to calibrate it more often.

Dave

Your suggestion would pass an ISO 9001:2000 audit?

 

[Duke Okes]

Rather than thinking of it as one set of 200 gages, think of it as 200 ring gages. Are all used at the same degree? If not, calibration could be set differently for various sizes, which might save a substantial amount.

 

[Wes Bucey]

FWIW:
My [relatively] small shop specializing in turning had as many as 20 or 30 tapered pipe thread ring gages for each size thread we ran, all mastered to the same plug master at the manufacturer (retained for our use only.) We had two or three on-site master plugs made as identical as possible to the manufacturer's master. We contracted with our customer to use gages also made and calibrated to the same master by our manufacturer. We would only have one ring gage for each machine running a specifc size thread. We would check each active gage every shift against our plug master. Any discrepancy got that ring taken out of service and cycled to the manufacturer for evaluation and either refurbished, calibrated and certified OR destroyed.

Because we had different size runs, setting refurbish/recalibrate by calendar instead of actual wear was not practical.

Our customers followed a similar policy. Having an ample inventory meant we ALWAYS had certified calibrated rings and never had to rush the manufacturer or deal with rings not calibrated to our "special" master.

OFF TOPIC:
we used stepped gages for tapered threads. The link may not be the best explanation, but it's the first I googled. http://welcome.gsgage.com/Tech CD Rev 1.0a PDF/4.1_Pipes.pdf

 

[Grizz1345]

I can see that I need to ask the question a little differently. Is there another way to calibrate thread ring gages? I find that using "set masters" is very subjective. It is almost imperative that they be checked to the master used to manufacture them. I find it hard to believe that 2 people using the same master could come up with the exact same numbers when calibrating a thread ring gage. From what I have learned the pitch is never measured, it is more of a "feeling" on a set master. Am I beating a dead horse here?

 

[Hershal]

Proper calibration of thread plugs, unless they are really really coarse, is accomplished using a supermic.....the environment is 20 C +/- 1 C, RH usually between 35-45%.....in other words.....

Send them to a calibration laboratory that is accredited to ANS/ISO/IEC 17025 for thread plugs, and have metrology professionals calibrate them.

The argument here for having metrology professionals calibrate your items instead of your folks calibrating them, is exactly the same as having machinists operate the CNC (or similar machines) instead of having the shipping clerk run them.....the metrology professionals have the proper equipment and environment, and the training and experience to make effective use of them.

Hope this helps.

Hershal

 

[Russ]

I am looking for feedback on how people approach the calibration of thread ring gages. My experience has been to return them to the manufacturer. I am really looking for a faster and more economical approach. I have approximately 200 sets of thread ring gages in my database. All comments would be appreciated.

We calibrate the majority of ours in-house using master plugs. It works for us.

Russ

 

[Wes Bucey]

I was always a great one for "division of labor" and never had any hesitation about outsourcing tasks outside of our core proficiencies. I could have easily put in a system to apply electroless nickel plating, but it would have meant nothing to our bottom line and very little to our quality, since we were very good at selecting competent suppliers of such service. Similarly, I have written elsewhere about dumping our grinding operation and getting better service in return.

Similarly, even with hundreds of plug and ring gages in addition to 3-wire mikes, snap ring gages, etc., I never found it cost-effective to even consider doing our own manufacture, refurbish, etc. It was sufficient for our purpose to check only active ring and plug gages against masters before each shift. If they didn't pass this perfunctory review, we put the problem in the hands of specialists and moved on to the next gage, since we only got paid for pieces we delivered to customers and preferred to devote our time and energy to that.

 

[kedarg6500]

We do not return thread gauges to the manufacturer. We have master thread plug gauges to check calibrated thread ring gauges & vice versa. All the gauges are spread over a year , hence we do not have issue of faster checking. It has not created any issue during ISO audit.