i have problem about npt thread design and gauging.it is about start and end diameters.
i have searched on internet and all people design it basing end diameter. they took major diameter as end diameter of thread ,there is no problem if you are design it with overalllengh.
but if you design it shorter than overall length.
end diameter will stay same and start diameter will decrease due to 1/16 taper.i understsnd this situation it can work with the internal thread but how they controll it with gauge?
also for bspt thread there is gage plane is there any certain point for npt thread?
thanks for answers.