Subject Classification

Since the beginning of an internal and external threads two;
Conodonts can be divided into: 1) triangle Thread 2) trapezoidal thread 3) rectangular thread 4) serrated;
3 by the number of rows of single-threaded and multi-start thread;
The direction of rotation of the left-hand thread and right-hand thread, right hand does not indicate the L-LH, the M93 × 1.5LH the;
5. According to different purposes: a common thread, metric thread seal pipe thread, non-thread sealing pipe thread, 60 ° tapered pipe thread, metric taper thread hydraulic manifold block
Metric ordinary thread
1 metric common thread with a capital M, tooth type angle 2alpha = 60 ° (alpha refers to the half-width of the tooth);
2 Metric ordinary thread, coarse thread and fine pitch two common thread pitch;
2.1 Coarse thread mark does not mean that on the pitch, such as M20 coarse thread, fine thread tag must show that on the pitch, such as M30 × 1.5 fine thread, where spacing of 1.5.
2.2 the connection between the mechanical parts and threaded connections are secured Coarse, fine thread is slightly higher than the same nominal diameter coarse thread strength, self-locking performance is better, generally used in common.
Métis tag common thread: M20-6H, M20 × 1.5LH-6G-40, where M denotes a metric thread, 20 thread public diameter of 20 mm, 1.5 means that pitch, LH left hand, 6H, each 6g said threaded accuracy level, capital precision level code, internal thread letter lowercase levels of precision, external thread 40 thread length;
The 3.1 common metric coarse pitch following table (threaded bottom outlet diameter: the carbon steel PHI = nominal diameter-P; cast iron Phi = nominal diameter -1.05 1.1P; the processing external thread diameter poles Phi = nominal diameter -0.13 P):valve block