Features: UNC - Unified National Coarse; This thread form was introduced in 1948 as an attempt to standardise thread forms in the USA, Canada and the UK. ; The thread profile of UNC is the same as for metric threads and is described in the JIS B0206 standard. ; The thread is described by its major diameter and the number of threads per inch of length (TPI). ; 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. ; It is also used on quick assembly or disassembly or if corrosion or slight damage is possible. ; Specifications:Diameter1/2"Pitch13 tpi