You know that PT threaded NPT thread, G thread, where is the difference between the metric thread?

National standards for GB/T7306. The NPT is National ( 美国) National standards for GB/T12716. National standards for GB/T7307. Inline people usually use points to call thread sizes, one inch equals eight points, and 1/4 inch is 2 points and so on. G is generally referred to as the pipe thread ( Guan) , 55, 60 degrees division belongs to functional, commonly known as round tube. The thread by a cylinder. Mid-december, commonly known as the tube cone, the thread surface is processed by a cone, the general water connection is such, national standard labeling for Rc. Metric thread by pitch, the inch thread used per inch in the number of thread, this is the difference between them. Metric thread is 60 degrees equilateral tooth type, inch thread tooth type is isosceles 55 degrees, American thread 60 degrees. Metric thread with metric unit, the inch thread used English unit. Common thread: metric thread M; The imperial W; Thread system UNC, UNE, features pipe thread: PS, PT, PF, American-made NPS, NPT thread of the wind, NPTF, NPSM: a quarter - CTV, TV 20 diameter size is 1 a: 0. 2367 - 0. 2489 ( 6. 012 - 6. 322). ; 2A:0. 2408 - 0. 2489 ( 6. 116 - 6. 322). 3A:0. 2419 - 0. 2500 ( 6. 1443 - 6. 350). 。 Pipe thread is mainly used for pipe connection, its internal and external thread cooperate closely, which has two kinds of straight tube and cone tube. Nominal diameter refers to the connection pipe diameter, apparently thread diameter larger than the nominal diameter. A quarter, 1/2, 1 / nominal diameter is 8 inch thread, the unit is inches. Thread Angle: metric and the us-made thread is 60 degrees, the imperial is 55 degrees, TM pipe thread is 30 degrees, SM needle thread and BC is 60 degrees, 30 degrees metric trapezoidal thread, imperial trapezoidal thread 29 degrees, Taiwan ( TW29 TR and TM30 degrees) 。 Inch thread: according to the nominal size and number of teeth per inch developing specifications such as 1/4 & quot; - - - - - - 20, 3/4' - - - - - - 10, 1' - - - - - - 8、1/4" - - - - - - 20 said nominal size 1/4 that big diameter is 6. 35毫米( 25. 4 in addition to 4 = 6. 35) 20 teeth per inch, and so on.