BSPT and BSP -the conical thread of British specifications

NPT — U.S. specifications of taper thread

PT -The old JIS specifications of Japan, which is equivalent to the ISO specifications R, RC

DIN2999 -Europe is mainly used in German pipelines

 

 

Different uses of threads can be divided into:

1. International Metric Thread System:

my country's national standard CNS uses threads. The top of the teeth is plane, which is easy to cut, and the bottom of the teeth is an arc -shaped to increase the thread strength. The thread angle is 60 degrees, and the specifications are represented by M. Public threads can be divided into two types: thick teeth and fine teeth. Represents such as m8x1.25. (M: code, 8: nominal diameter, 1.25: snail distance).

2. American Standard Thread:

The top and roots of the thread are flat, and the strength is better. The threaded horn is also 60 degrees, and the specifications are expressed in a few teeth per inch. Such threads can be divided into coarse teeth (NC); fine teeth (NF); sessions (NEF) level three. Represents a 1/2-10nc. (1/2: outer diameter; 10: number per inch; NC code).

3. Uniform standard thread (unified thread):

It is formulated by the United States, the United Kingdom, and Canada, and is currently used in British threads.

The threaded horn is also 60 degrees, and the specifications are expressed in a few teeth per inch. Such threads can be divided into coarse teeth (UNC); fine teeth (UNF); minimal teeth (UNEF). Represents a 1/2-10UNC. (1/2: outer diameter; 10: number per inch; UNC code)

4. V -shaped thread (Sharp V Thread):

Both the top and the roots are pointed, the strength is weak, and it is not commonly used. The thread angle is 60 degrees.

5. Whitworth Thread:

British national standards use threads. The thread angle is 55 degrees, indicating that the symbol is "w".

Suitable for rolling method manufacturing. Represents such as W1/2-10. (1/2: outer diameter; 10: number per inch; W code).

6. Knuckle Thread:

Standard threads set by German DIN. Suitable for the connection of light bulbs and rubber tubes. The symbol is "RD".

7. Pipe Thread:

To prevent leaks from leakage, it is often used in the connection of gas or liquid pipes. The thread angle is 55 degrees, and it can be divided into the straight tube thread code as "P.S., N.P.S." and the slashing tube thread code code "n.p.t.", which is 1:16, that is, 3/4 inches per foot.

8. Square Thread:

The transmission efficiency is high, second only to the roller thread, and the nut can not be adjusted after wear, for its disadvantages. Generally used for the screw and thread of the tiger's clamp.

9. Trapezoidal Thread:

Also known as the Ekim thread. The transmission efficiency is slightly smaller than the square thread, but it can be adjusted with nuts after wear. The screw angle of the public system is 30 degrees and the screw angle of the British system is 29 degrees. Generally used for the guidance screw of the lathe. The symbol is "TR".

 

10. Buttress Thread:

Also known as a trapezi thread, it is only suitable for unilateral transmission. Such as the spiral jack, compressor, etc. The symbol is "bute."

11. Rolling snail:

It is the best thread for transmission efficiency. It has difficulty in manufacturing and is extremely costly. It is used for precision machinery. Such as the guide screw of the CNC tool machine