These thread cutter sets include a tool for exterior threads and one for cutting matching interior threads. Perfectly designed for making screw tight lids on boxes and caskets, this fascinating and practical aspect of woodturning includes a range of cutting tools that have been produced from High Speed Steel (HSS) in 10, 16, and 20 threads per inch (TPI). They have been designed with a unique, enhanced helix angle specially designed for use in wood.