Accurate thread ring gauges are crucial for quality and consistency of threaded parts. This article outlines the procedure for setting a thread ring to a master setting plug, as per ANSI B1.2 standards.

Gage Assembly, a leading manufacturer of precision thread plug and ring gages, serves the aerospace, energy, defense, oil and gas, and automotive industries.

Deltronic manufactures pin gages, thread measuring wires, and gear wire measuring wires in inch and metric sizes.  Also, Deltronic’s Alameda line offers premium thread, ring, plug and pipe gages.

In my last column I listed some basic equipment requirements for the calibration of thread plug gages so I thought it would be helpful to give mating gages the same treatment. 

You’ve made the threaded parts and are confident they are okay because you’ve checked them with your gages. Then you get the call from the customer advising you that their gages have rejected the parts and they are demanding re-work or replacements ASAP.

One would think that when you get your thread ring gages calibrated and there are no red flags raised by the reported data you’re good to go. Unfortunately, this sea of tranquility can end up drowning you if you have misinterpreted the reports—something that happens when disputes arise.

External thread inspection can seem confusing and, in some cases, frustrating. There is a wide variety of inspection tools available for external threads.

A reader emailed me after reading some of my rants on thread ring gages dealing with the problems that come up in their use and calibration. But he added another dimension to the problem since he is in the calibration business: How do the Europeans deal with their solid thread ring gages?

When difficult part features need to be qualified a coordinate measuring machine (CMM) can be the answer for an awkward problem.

The previous two columns dealt with a study of thread plug gage calibration, the results of which will be discussed and/or argued over for some time.