When the thread precision requirements are high, in add […]
When the thread precision requirements are high, in addition to marking the thread code, the thread tolerance zone code and thread engagement length should also be marked.
The marking format of the thread mark is:
Thread code-thread tolerance zone code (pitch diameter, top diameter)-screwing length
l) Tolerance zone code is represented by numbers and letters (capital letters for internal threads, lowercase letters for external threads), such as 7H, 6g, etc. It should be particularly pointed out that 7H, 6g, etc. represent thread tolerances, while H7, g6 represent cylinder tolerances Codename.
2) The screwing length is specified as short (represented by S), medium (represented by N), and long (represented by L). Under normal circumstances, the screwing length is not marked, and the thread tolerance zone is determined by the medium screwing length (N). If necessary, you can add the code S or L for the screw length, such as "M20-5g6g-L". For special needs, the value of the screwing length can be indicated, such as "M20-5g6g-3
Ordinary thread
Ordinary coarse thread: feature code M + nominal diameter + direction of rotation + thread tolerance zone code (pitch diameter, top diameter)-screw length
Ordinary fine thread: feature code M + nominal diameter * pitch + rotation direction + thread tolerance zone code (pitch diameter, top diameter)-screwing length
Right-hand thread is omitted without note, and left-hand thread is indicated by "LH".
M 16-5g6g means coarse general thread, nominal diameter 16, right-handed, thread tolerance zone 5g in the middle diameter, 6g in the major diameter, the screwing length is considered as medium length.
M16×1 LH-6G means fine-tooth ordinary thread, nominal diameter 16, pitch 1, left-handed, thread tolerance zone diameter and major diameter are both 6G, and the screwing length is considered as medium length.
Marking of pipe threads
The format is: feature code (G for cylindrical pipe thread and NPT for tapered pipe thread) + size code + tolerance class code + direction of rotation
G1A--LH means inch non-threaded sealing pipe thread, size code is 1in, right-handed, tolerance class is A level.
Rcl/2 means inch thread sealing taper pipe thread, size code 1/2in, right-handed.
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