The nominal size of a Taper Pipe Tap (NPT) is that of the pipe fitting to be tapped, not the actual size of the tap. 3/8-18, pipe taps, straight pipe (nps), high speed steel, bright
Features
The nominal size of a Taper Pipe Tap (NPT) is that of the pipe fitting to be tapped, not the actual size of the tap.
The Interrupted Thread Pipe Taps have every other thread removed except for the first few at the point.
They are used for tapping tough metals or those which have a tendency to load the tap teeth.
Straight Pipe Taps (NPS) are used for hand or machine tapping of straight pipe threads.