Questions about interface dimensions

M20X1.5: 20 refers to the diameter, 1.5 refers to the pitch; Φ8 refers to the outer diameter; G1/4 refers to imperial threads; 1/4NPT refers to tapered threads

Rc1/4 is a sealed tapered pipe thread with a nominal diameter of 1/4 inch； 1/4NPT is the American tapered pipe thread ； G1/4 is a pipe thread ； Φ8 is a diameter of 8mm ； M20×1.5 is a regular thread with a nominal diameter of 20 mm and a pitch of 1.5 mm. The above are different connection standards and cannot be converted.

NPT, PT, and G are all pipe threads. NPT is the abbreviation for National (American) Pipe Thread; it represents a 60-degree tapered pipe thread standard used in North America. **For the relevant standard, refer to** GB/T12716-1991. PT is an abbreviation for Pipe Thread; it refers to a 55-degree sealed tapered pipe thread that belongs to the Whitworth thread family. It is widely used in Europe and the Commonwealth countries. It is commonly employed in the water and gas piping industries, with a taper ratio of 1:16. The relevant standard can be found in GB/T7306-2000. G is a 55-degree unthreaded sealing pipe thread, belonging to the Whitworth thread family. The designation G indicates a cylindrical thread. **The standard can be found in GB/T7307-2001. Additionally, the 1/4, 1/2, 1/8 designations in threads refer to the diameter of the thread size, measured in inches. Those in the industry usually refer to thread sizes in terms of fractions; one inch equals 8 fractions, so 1/4 inch is 2 fractions, and so on. G is the general term for pipe threads; the classifications of 55 and 60 degrees are functional in nature and are commonly known as pipe circles. That is, the thread is formed by machining a cylindrical surface. ZG is commonly known as pipe taper, meaning that the threads are formed by a conical surface; most water pipe fittings use this type of thread. According to national standards, metric threads are denoted by pitch, while imperial and British threads are indicated by the number of threads per inch – this is their main difference. Metric threads have an equilateral tooth profile at 60 degrees, British threads have an isosceles tooth profile at 55 degrees, and American threads also have a 60-degree tooth profile. Metric threads use metric units, while imperial and American threads use imperial units. Pipe threads are primarily used for connecting pipes; their internal and external threads fit tightly together, and there are two types: straight pipes and tapered pipes. The nominal diameter refers to the diameter of the pipe being connected; obviously, the thread diameter is larger than the nominal diameter. 1/4, 1/2, 1/8 are the nominal diameters of imperial threads, measured in inches. BSP is the British standard for cylindrical pipe threads, while BSPT is the British standard for tapered pipe threads: these threads have a thread pitch angle of 55° and a taper ratio of 1:16. RC refers to the sealed tapered internal thread at 55 degrees; GB/T7306.2-2000 R2 denotes the tapered external thread that mates with the tapered internal thread per GB/T7306.2-2000

M20X1.5: 20 refers to the diameter, 1.5 refers to the pitch; Φ8 refers to the outer diameter; G1/4 refers to imperial threads; 1/4NPT refers to tapered threads