60 ° sealing pipe thread gauge inspection

1 Scope: This standard specifies the tooth shape, basic dimensions, tolerances, markings, and gauges for pipe threads (NPT and NPSC) with a tooth shape angle of 60 ° and a sealed thread body. This standard applies to the tight threaded connection of pipes, valves, pipe joints, cocks, and other pipeline accessories. The following normative references are essential for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest version (including all modification orders) applies to this document. GB/T 14791 Thread Terminology 3 Terms and Designations 3.1 Terms and Definitions GB/T 14791 defines and the following terms and definitions apply to this document. 3.1.1 When inspecting threads with a reference plane gauge, read the visible plane of the workpiece referenced by the inspection value (positional deviation of the reference plane). It is the outer end face of an internally threaded component or the small end face of an externally twisted component. 3.2 Code D - Major diameter of internal thread in the reference plane; D - The major diameter of the external thread within the reference plane; D - The diameter of the inner screw in the reference plane; d: - The pitch diameter of the external thread within the reference plane; D - The minor diameter of the internal thread in the reference plane; d. - The minor diameter of the external thread within the reference plane; N - the number of teeth included within an axial length of 25.4 mm; P - Creep distance; H - - Original triangle height; H - Thread profile height; F - Leveling height; L - reference distance; L - effective thread length; L. - Assembly allowance; L. - Full thread length; 1—— Incomplete thread length