Answer
Jul 27, 2022 - 08:43 AM
NPT and PG thread are somewhat different in size and shape. NPT threads are tapered at a rate of 1/16, while PG threads are straight. The depth of a PG thread is smaller than NPT threads, but the flank angle is larger. 1" NPT has a 1.32" outer diameter with a pitch of 0.087". PG 21 thread has an outer diameter of 1.11" and a pitch of 0.062".
