NPT, PT, G are pipe threads

NPT is an abbreviation of National (American) Pipe, which belongs to the United States standard 60 degree taper pipe thread, used in North America. National standard can be consulted GB/T12716-1991 Thread

PT is the abbreviation of Thread Pipe, is a 55 degree taper pipe thread sealing, belonging to the Whitworth family, for the European and Commonwealth countries. Commonly used in water and gas pipe industry, taper regulations of 1:16. national standard is available on the GB/T7306-2000

G is a 55 degree non threaded sealing pipe thread, which belongs to the GB/T7307-2001 family. It is marked with G

In addition, the 1/4 pipe thread 1/2, 1/8 markers are used with threaded hole of the pipe diameter, rather than the diameter of the thread, in inches. Insiders usually used to call thread size, one inch to 8 inches, 1/4 is 2,.G is referred to as so on pipe threads (Guan, 55), division 60 degrees are functional, commonly known as the tube. That is, the thread is processed by a cylindrical surface.

ZG is a commonly known as cone, cone thread processing, pipe joint is generally labeled as such, GB Rc for metric threads to represent the thread pitch, expressed per inch thread number, this is the biggest difference between them is 60 degrees, metric thread edge tooth type. 55 inch thread is isosceles tooth type of thread, 60 degrees. Metric thread metric unit, and thread with imperial units. The pipe thread is mainly used for the connection of the pipe, and the internal and external threads are closely matched with two kinds of straight pipe and a conical pipe. The nominal diameter is the diameter of the connected pipe, obviously the diameter of the thread is larger than the nominal diameter. 1/4, 1/2, 1/8 is the nominal diameter of the thread, the unit is in.

BSP thread from the British Whitworth pipe, and whitworth thread series combined Whitworth established basic dimensions. According to the relationship between the imperial pipe thread taper 1/16, radial diameter whitworth thread into axial teeth sealing pipe threads (inch tolerance in a certain amount of rounding and). According to the adjustment value of the imperial non sealing pipe thread sealing pipe thread tolerances inch tolerances (tolerances by one-way distribution into a one-way distribution, relax the top diameter tolerance, open bottom diameter tolerances).