Recently, I was confused by different threads requirements in different clients’ drawings. In order to figure out the differences, I accessed relevant information and summarized as below:
Pipe thread: mainly used for pipe connection, the internal and external thread can be tight, it has straight tube and cone tube two specifications.
Common pipe thread mainly include the following: NPT, PT, G and so on.
- NPT thread: American standard 60 degree tapered pipe thread
NPT: full name is National Pipe Thread, Belonging to the US standard 60 degree tapered pipe thread, used in North America, access GB / T12716-1991.
- PT(BSPT) thread: European and Commonwealth 55 degree sealed cone thread
PT(BSPT): full name is British Standard Pipe Thread, is 55 degrees sealed cone thread, belonging to the Wyeth thread family, used in Europe and Commonwealth countries, commonly used in water and gas pipe industry, taper 1:16, access GB / T7306-2000.
- G thread: 55 degree non-threaded sealing pipe thread
G is a 55 degree non-threaded sealing tube thread, is a Wyeth thread family. Marked as G, means the cylindrical thread. GB / T7307-2001.
The difference between metric threads and inch threads:
Metric threads are represented by pitch, while US-inch threads are represnted by the number of threads per inch;
Metric thread is equilateral 60 degrees tooth type, inch thread is isosceles 55 degrees tooth type, American thread for the waist 60 degrees tooth type.
Metric threads in metric units (e.g. mm), American and British-made threads in inch units (e.g. inch)
If there is other information I have not mentioned, or if there is any mistake, keep me informed.
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