Ordinary coarse thread: characteristic code M + nominal diameter + rotation + thread tolerance zone code (middle diameter, top diameter) - rotation length
Ordinary fine thread: characteristic code M + nominal diameter * pitch + rotation + thread tolerance zone code (middle diameter, top diameter) - rotation length
The right-hand thread is omitted and the left-hand thread is indicated by "LH".
M 16-5g6g indicates coarse thread common thread, nominal diameter 16, right-handed thread, thread tolerance zone middle diameter 5g, major diameter 6g, and the rotation length is considered as medium length.
M16×1 LH-6G represents ordinary thread with fine teeth, nominal diameter 16, pitch 1, left-handed, and the diameter and diameter of the thread tolerance zone are all 6G. The length of the threading is taken into consideration for the medium length.
The labeling format is: Signature code (indicated by G for cylindrical pipe thread, NPT for taper pipe thread) + Dimension code + Tolerance class code + Rotation direction
G1A--LH represents the inch non-threaded sealing pipe thread, size code 1in, left-handed, tolerance class A.
Rcl/2 stands for inch threaded taper pipe thread, size code 1/2in, right handed.