Drill America DWT Series Qualtech pipe tap is appropriate for threading a wide variety of materials both ferrous and non-ferrous. The nominal size of a pipe tap is that of the pipe fitting to be tapped, not the actual size of the tap. The thread tapers 3/4 of an inch per foot. All pipe taps furnished with a 2-1/2 to 3-1/2 thread chamfer. NPT threads require the use of a "sealer" like Teflon tape or pipe compound. High-speed steel tool is good for most general purpose applications, offering a combination of hardness and toughness for wear resistance. Uncoated tools feature just the base substrate without any additional treatment or coatings and are suitable for a wide range of applications. Straight flute tools allow chips to collect in the flutes as they cut and are well suited for most applications in shallow cuts. Right-Hand cut tools have a cutting action that engages when they are run in a clockwise direction.