These are to indicate the screw holes 3-M2-6H as an example, 3 indicates that there are 3 screw holes on a piece, M2 is the size of the screw holes, there is a standard for the size of the screw holes, and 6H indicates the depth.
These are indicated thread 3-M2-6H as an example, 3 indicates that there are 3 on the workpiece, M2 is a variation of the thread diameter of 2mm, 6H indicates that the base hole system of 6 levels of accuracy, even distribution for the average distribution (in a straight line and on the circumference), the depth of 6 indicates that the depth of 6 (mm). G indicates the pipe thread, Z indicates the taper thread, and the national standard of the corresponding indicates the shape of the thread teeth.
Threaded teeth processing
For fastening threads and transmission threads without transmission accuracy, the surface processing of threads refers to the dimensional accuracy of the required center and top diameters. For the transmission progress requirements of the transmission thread, in addition to the requirements of the dimensional accuracy of the center and top diameters, but also requires the pitch and shape accuracy of the tooth type, but the domestic standard value of the center and top diameters of the dimensional accuracy of the pitch and shape accuracy of the tooth type by the center diameter of the dimensional accuracy of the guarantee.