HSS UNC Intermediate Hand and Machine Tap Unified National Coarse thread form was introduced in 1948 as an attempt to standardise thread forms in the USA, Canada and the UK Manufactured from HSS this general purpose tap is designed for use in medium tensile materials and is for hand or general machine use
The thread is described by its major diameter and the number of threads per inch of length (TPI). The thread profile of UNC is the same as for metric threads and is described in the JIS B0206 standard. This thread series is commonly used in the mass production of bolts, screws and nuts. It is used for threading into lower tensile strength materials (bronze, brass, aluminium and plastics) to obtain the best resistance to stripping of the internal thread, making it a reliable machine tap.
