npt thread gage common practice

[PETE1968]

i was always taught that +/- 1 turn from flat on pipe gage was the process. is this correct standard and where can i find this info.

thanks pete

[lakeside]

here some info I copy from the machinist handbook if you need something else let me know and I look it up for you as for plus or minue a thread now way it got to be at the flat by hand when you put a wrench on it it will either be to deep and bottom out with out sealing or it may not be enough of seal at all the jpeg not that great so if you need a copy I send it to you