Taper Pipe Taps ? NPT taper pipe taps are commonly used for tapping pipe fittings and couplings in a wide variety of materials. Assembly requires the use of a thread sealant to ensure a tight seal. ? Interrupted Thread taper pipe tap reduce friction, increase chip capacity and enhanced coolant flow to the cutting teeth for reduced chance of torn threads and improved thread quality. Recommended for a wide variety fo materials, especially soft ductile materials and materials producing long continuous chips.