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Introduction of common threads

Time : 2022-07-20 Hits : 5


American ORFS thread is O-ring ON FACE SEAL, which means "O-ring ON FACE SEAL". Generally, UNF thread is sealed in this way.

Thread is a continuous convex part with a specific cross section made on the surface of a cylindrical or conical matrix. Thread is divided into cylindrical thread and taper thread according to its parent shape; According to its position in the mother is divided into external thread, internal thread, according to its section shape (tooth) is divided into triangle thread, rectangular thread, trapezoidal thread, serrated thread and other special shape thread.




JIC standard are usually fine thread.



The thread diameter is: inches X25.4

3/8 is 0.375 inches. Standard coarse teeth are 16 teeth per inch

A quarter is 0.250 inches. Standard coarse teeth are 20 teeth per inch

The Fittings Industrial Council. 

1 national standard, national standard has A B C D F H six forms

Type A is flat O-ring seal metric thread TYPE B for GB card sleeve type C form GB 74 degree cone TYPE D for spherical type

Type F is flange and sealed in accordance with SAE standards, while Type H is sealed with 24 degree cone and O-ring, but there are several specifications different from German standards.

2 German standard: a large number of metric 24 degrees cone O ring sealing flange and the national standard.

3 American standard has JIC standard and ORFS standard, JIC is American thread, 74 degree cone,ORFS is American thread, plane sealing but sealing groove is different from national standard.

JIS standard inch pipe threads, 60 degree taper.


BSPT is the British standard for taper pipe threads.

BSPT is the British standard for tapered pipe threads: the thread profile Angle is 55° and the thread has a 1:16 taper

BSPT British Standard Pipe Thread