It's really not important at all as long as the bore and truncation and/or rounding is large enough to clear the features of the root, in the event the male thread being inspected is at maximum material conditions allowed for a certain class of threads.
Since we are usually measuring the pitch diameter and to a far lesser extent the major diameter I would say that if there is a reason to inspect the root diameter and its features (fillets, width of flat, etc.) then a special set of go/no go gauges designed specifically for root inspection would need to secured.
It's practically impossible to measure the crest, pitch, and root diameters of any male thread and just use one (1) type of go/no go guage.
If this is a go ring gage, the minor diameter is very important. The minor diameter verifies that the root at the bottom of the thread has not become to large. You can measure the pitch diameter and have it in tolerance while the thread will not function due to the root being to large. Depending on the size of the thread, all the features stated to be impossible to measure can easily be measured on an optical comparator. This should be common quality equipment for any house that cuts threads.
Thank you very much for your information. We are gauge makers in India. Recently one of our new customer, had ordered a Thread Ring Gauge with us. Reducing the major, pitch and monor diameter by about 4 to 6 microns from the standard class of fit. This was required to manufacture a component that is to be exported to a client in USA. The American client has specified the dimension to their Indian client here, and we were contacted to manufacture the particular gauge. Since it is a smaller diameter gauge we had to adopt the practice of tapping & lapping and finally check the gauge with a Check Plug that was created before hand as per the specification.
We had truncated the minor diameter as per practice and norms laid down by the ISO standards, the client is a bit jiffy about the minor diamerter. We had a doubt in this respect that is why we put a question about the same.
However, thank you very much once again and wish you a very happy new year .
Form, Fit and Functionality get some mating parts from the customer if possible, that will give clearer answers to how important the Minor Diameter is.
Thread Ring Gauge Solid Type
Re: Thread Ring Gauge Solid Type
