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Description of ORFS threads

2022-09-24 Page view : 4 views

ORFS thread is O-ring ON FACE SEAL, is “O RING in the end FACE SEAL” meaning, generally UNF thread adopts this SEAL.

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

R is the radius difference from the start point to the end fittings, and the outer taper thread R is negative and the inner taper thread is positive
We are swaged hose fittings manufacturer.

The United States unified thread, widely used in inch countries, this kind of thread is divided into three series: coarse teeth series UNC, fine teeth series UNF, extra fine teeth series UNFF, plus a constant pitch series UN.
Marking method: Thread diameter – number of teeth per inch series code – precision class
Example:
Coarse teeth Series 3/8 — 16 UNC — 2A
Fine tooth series 3/8 — 24 UNF — 2A
Extra fine teeth series 3/8 — 32 UNFF — 2A
Constant pitch series 3/8 — 20 UN — 2A
The first digit 3/8 (fraction or decimal) indicates the outside diameter of the thread in inches. To convert mm into metric units, multiply by 25.4, i.e., 3/8×25.4=9.525mm; The second and third digits 16, 24, 32, 20 are the number of teeth per inch (the number of teeth on 25.4mm length); The characters after the third digit UNC, UNF, UNFF, UN are series codes, and the last two digits 2A are accuracy levels.

UN system thread is the United States, Britain and other fittings development of the British dimension based on the thread standard, called unified thread, used to call the United States system thread (because in the United States is widely used, The unified thread has coarse thread (UNC), fine thread (UNF), ultra-fine thread (UNEF), special thread (UNS), fixed thread (4UN(4 teeth per inch), according to the number of teeth per inch). Similarly below), 6UN, 8UN, 12UN, 16UN, 20UN, 28UN and 32UN), and for external threads, there are UNR threads with circular arc at the bottom.