GearWrench 82862N 1/4 – 18 NPT Tap The GearWrench 82862N 1/4 – 18 NPT Tap features tapered cutting edges, which give a less aggressive cut than plug taps in small diameters. Manufactured from carbon steel, the GearWrench 82862N 1/4 – 18 NPT Tap has clear laser-etched size markings for easy identification.