Pipe and Conduit Thread Tap, Thread Size 3/8 In.-18, NPT, Overall Length 2 9/16 in, High Speed Steel, TiN, Right Hand, Thread Length 1 1/16 in, 75 Percent Thread Drill Size 9/16 in, Number of Flutes 4 High-performance pipe and conduit taps provide better wear resistance than other high-speed steel pipe and conduit taps when threading holes in workpieces made from specific materials. These taps are made from HSS-E, a type of high-speed steel that has a higher percentage of cobalt and vanadium than standard high-speed steel.