For making practical wooden threads with a virtually unlimited number of applications for making furniture, racks, toys, nutcrackers, lamps etc. Two-piece set (threading box and tap), for cutting internal and external threads. The stated tap hole diameters are reference values. The ideal diameter in each case should be determined by test drillings depending on the type of wood and preferred fit. Tap made of hardened tool steel, hardwood thread box with a removable hardened steel cutter. The pitch corresponds to the number of thread tips per inch. Fits maple dowel rods No. 831548, 831549, 831550, 831551 and 831552. Comes with instructions.