Ordinary thread

Common coarse thread: feature code M+nominal diameter+direction of rotation+thread tolerance zone code (pitch diameter, top diameter) - screw-in length
Ordinary fine pitch thread: feature code M+nominal diameter * pitch+direction of rotation+thread tolerance zone code (pitch diameter, top diameter) - screw-in length
Right-handed thread is omitted, and left-handed thread is indicated by "LH".
M 16-5g6g refers to coarse thread, nominal diameter 16, right-handed, pitch diameter 5g, major diameter 6g in thread tolerance zone, and screw-in length is considered as medium length.
M16 × 1 LH － 6G refers to fine-tooth common thread, with nominal diameter of 16, pitch of 1, left-hand rotation. The pitch diameter and major diameter of thread tolerance zone are 6G, and the screw-in length is considered as medium length.
The dimension format is: feature code (G for cylindrical pipe thread and NPT for conical pipe thread)+dimension code+tolerance class code+rotation direction
G1A - LH refers to the British non-threaded sealing pipe thread, the size code is 1in, left-handed, and the tolerance class is Grade A.
Rcl/2 refers to British thread sealing taper pipe thread, size code 1/2in, right-handed.