Pipe threads are mainly used for connecting pipes, making their internal and external threads fit tightly. There are two types: straight pipes and tapered pipes. The common types of pipe threads include NPT, PT, G, etc.

The common types of pipe threads include NPT, PT, G, etc.

(1) NPT is the abbreviation for National (American) Pipe Thread, which belongs to the American standard of 60 degree taper pipe thread and is used in North America. The national standard can be found in GB/T12716.

(2) PT (BSPT) is the abbreviation for Pipe Thread, which is a 55 degree sealed conical pipe thread belonging to the Wyeth thread family. It is commonly used in Europe and Commonwealth countries, and is commonly used in the water and gas pipe industry. The taper is 1:16, and the national standard can be found in GB/T7306. The domestic name is ZG.

(3) G is a 55 degree non sealed pipe thread, belonging to the Wyeth thread family. Marked as G represents cylindrical thread. Refer to GB/T7307 for national standards.

Metric and imperial threads

Metric threads are represented by pitch, while American and British threads are represented by the number of threads per inch;

The metric thread has a 60 degree equilateral tooth profile, the British thread has an isosceles 55 degree tooth profile, and the American thread has an isosceles 60 degree tooth profile;

Metric threads are measured in metric units (such as mm), while American and British threads are measured in imperial units (such as inches);

"Insiders" usually use "minute" to refer to thread size. One inch is equal to 8 minutes, 1/4 inch is equal to 2 minutes, and so on.

In addition, there is also the ISO metric thread standard of 60 degrees; UN - Unified thread standard of 60 degrees; API - American Petroleum Pipe Thread Standard 60 degrees; W-British Wyeth thread standard 55 degrees.

Differences in various threads：

NPT, PT, and G are all pipe threads

NPT is the abbreviation for National (American) Pipe Thread, which belongs to the American standard of 60 degree taper pipe thread and is used in North America. The national standard can be found in GB/T12716

PT is the abbreviation for Pipe Thread, which is a 55 degree sealed conical pipe thread belonging to the Wyeth thread family and is commonly used in European and Commonwealth countries. It is commonly used in the water and gas pipe industry, with a taper specification of 1:16. National standards can be found in GB/T7306

G is a 55 degree non threaded sealing pipe thread, belonging to the Wyeth thread family. The symbol G represents cylindrical thread. The national standard can be found in GB/T7307

In addition, the 1/4, 1/2, and 1/8 marks in threads refer to the diameter of the thread size, measured in inches. Insiders usually refer to thread size in minutes, where one inch is 8 minutes and 1/4 inch is 2 minutes, and so on. G is the general term for pipe threads (Guan). Divisions of 55 and 60 degrees are functional and commonly referred to as pipe circles. The thread is machined from a cylindrical surface.

ZG, commonly known as pipe cone, refers to a thread made from a circular conical surface. Generally, water pipe joints are marked as Rc in the national standard. Metric threads are represented by pitch, while American threads are 60 degrees. Metric threads are measured in metric units, while American and British threads are measured in imperial units. Pipe threads are mainly used for connecting pipes, and their internal and external threads fit tightly, with two types: straight pipes and tapered pipes. The nominal diameter refers to the diameter of the connected pipeline, and obviously the thread diameter is larger than the nominal diameter. 1/4, 1/2, and 1/8 are the nominal diameters of inch threads.