Wheatland manufacturers a full line of complementary tubular fittings nipples, elbows, couplings and running thread made from the same materials as our raceways. couplings are ID threaded from metal stock that has its ID sized, so when threaded, it will mate with the OD threads of the conduit. the pitch of conduit threads conforms to the America National Standard for pipe Threads, General Purpose (Inch), ANSI/ASME B1.20.1. the taper of threads is 3/4 in per foot (1 in 16).