This Part of GB/T 5796 specifies the tolerances and markings for trapezoidal threads. The tooth type and diameter and pitch series of trapezoidal thread comply with the provisions of GB/T 5796.1 and GB/T 5796.2 respectively. This part applies to trapezoidal thread connections for general-purpose mechanical transmission and fastening, and does not apply to trapezoidal threads with special requirements for axial displacement, such as precision drive screw.