Thread standard - BSPP, BSPT,NPT(G,Rc，NPT)

Thread standards refer to a series of standards that specify parameters such as tooth profile, diameter, and pitch of threads. These standards ensure that threads from different countries and regions can be interchanged and used, mainly divided into international metric standard threads, American standard threads, and uniform standard threads. ‌

International Metric Thread System 
The international metric standard thread is the thread adopted by China's national standard CNS, with a flat tooth crest that is easy to turn and a circular arc tooth base to increase thread strength. The thread angle is 60 degrees, and the specification is represented by M. Metric threads can be divided into coarse and fine threads, represented by M8x1.25 (M: code, 8: nominal diameter, 1.25: pitch).

American standard thread
The top and root of the American standard thread are both flat, with better strength. The thread angle is also 60 degrees, and the specification is expressed as the number of teeth per inch. This type of thread can be divided into three levels: coarse thread (NC), fine thread (NF), and ultra-fine thread (NEF). Representations such as 1/2-10NC (1/2: outer diameter, 10: number of teeth per inch, NC code).

Unified standard thread
The unified standard thread was jointly developed by the United States, the United Kingdom, and Canada, and is currently the commonly used imperial thread. The thread angle is 60 degrees, and the specification is expressed as the number of teeth per inch. This type of thread can be divided into coarse thread (UNC), fine thread (UNF), and ultra-fine thread (UNEF). Representations such as 1/2-10UNC (1/2: outer diameter, 10: number of teeth per inch, UNC code).

British thread
Imperial threads include Hui style threads and pipe threads. The thread angle of Hui style thread is 55 degrees, suitable for rolling method manufacturing. Pipe threads are mainly used for pipeline connections, with two types: straight pipes and tapered pipes. Common ones include NPT, PT, G, etc.

Specific application scenarios
International metric standard thread: widely used for connecting mechanical components that require high strength and precise dimensions.
American standard thread: commonly used in the industrial and construction fields of the United States and its allies.
Unified standard thread: widely used in the international market, especially in situations where interchangeability is required.
British thread: mainly used in the industrial and construction fields of Britain and its former colonies.