Wayne,
Thank you for all the excellent information.
The last paragraph of 7.1.1. reads "Partial end threads shall be removed on both ends of the ring gage and on the small end of the plug gage to full-form profile in order to avoid possible seating error from bent or malformed feathered edge."
As you can see, it's not as detailed as NPTF. PM me for a copy.
Have you ever seen a survey of measured L1 numbers for female threads across different manufacturers? I would think that the more expensive fittings mfrs would use this to show how their products meet spec and those of competitors often don't.
A general question, agree, disagree, or comment:
Threads on pipe nipples tend to be correct dimension because those are governed by taper angle and number of threads. The OD of the pipe is fairly tightly controlled, the taper angle doesn't change that much with tool wear, and the number of threads is plainly visible, so if it's wrong the product tends to get rejected with no measurement needed.
In contrast, female threads tend to be undersized (i.e. they have short L1's) because they have no reference dimension equivalent to pipe OD, and as long as they have all their threads, plus short hand-tight lengths in the field can be easily chalked up to dings and burrs. It pays for manufacturers to cut corners here because it's cheaper to leave the hole smaller and no one notices.
Thanks again, Wayne!