Uniform inch thread

Unified British threads include coarse (Unified National Coarse, UNC), Fine teeth (Unified National Fine, UNF)、Extremely Fine Teeth (Unified National Extra-Fine, UNEF), and Diamond teeth 4UN, 6UN, 8UN, 12UN, 16UN, 20UN, 28UN, 32UN. The mountain shape is an acute angle, and the angle of the mountain is 60°. The unified representation method of inch threads is not to directly indicate the "pitch" like metric threads, but to express "the number of threads per inch".

Thread representation
[Name diameter] - [Number of teeth per inch] [Tooth shape]
¼ - 20 UNC
⁵⁄₈ - 12 UN
unified thread

ANSI / ASME B1.1 Unified inch thread Series

Unit mm