calibrationd said:
What is the proper way to calibrate tapered thread plugs?
The simplest and surest way to get a definitive answer is to go back to your tapered plug gage manufacturer and get female ring masters. I preferred the multi-step ones. You can ask the manufacturer for a procedure which will suit your operation.
I found it effective to thread each plug into its master and use a drop gage to check the difference between the top of the plug and the top of the female ring and chart that measurement. Obviously, when the male starts to go deeper into the female ring, it is exhibiting wear. At that point, you can either perform your own measurements for certification or send it to a certification lab.
(Note the ring gages have to be kept strictly for the calibration and NOT used for production. There is a lot of opportunity for individual variation in "feel" for how much torque is exerted in using the plug.
[absolutely have to avoid tendency of newbies to want to cut new threads on the plug by forcing it into the master ring.] The ring and the plug have to be scrupulously clean.)