The profile angle of T-thread is 30, which is mainly used for the transmission and fastening of large-size parts.

The national standard for T-bolts is:

GB/T 2165-1991T-groove quick release bolt for machine tool fixture parts (obsolete) was adjusted to JB/T 8007.2- 1995, and later changed to JB/T8007.2-1.

GB/T 37- 1988 T slot bolt

There are also mechanical standards: JB/T1709-1T bolts (obsolete), which have been replaced by JB/T 1700-2008 valve parts nuts, bolts and plugs.

At present, DIN 186 T square neck bolt, GB37 and DIN 188T double neck bolt are commonly used, which are made of carbon steel, stainless steel and alloy steel. Specifications range from M8-M64, and Musheng, which is well-controlled in China, has formed a mature technology.