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]

Example

¼ - 20 UNC

⁵⁄₈ - 12 UN

ANSI / ASME B1.1 Unified inch thread Series

• UNC
• UNF
• UNEF
• 4 UN
• 6 UN
• 8 UN
• 12 UN
• 16 UN
• 20 UN
• 28 UN
• 32 UN