Information
Pipe thread
Pipe threads are commonly used in gas and water installation technology. The parameter is given in inches and originally referred to the inside diameter or nominal diameter (DN) of medium-heavy threaded pipes. However, light and heavy threaded pipes with different wall thicknesses are also commonly used for the same nominal size.
From today's perspective, the reference to inside diameter is rather obstructive and confusing:
In Europe, the Whitworth thread is commonly used. It is also abbreviated to BSP (cylindrical thread) (British Standard Pipe).
According to the standard , a distinction is made between thread-sealing(EN 10226-1, previously: DIN 2999) and non-thread-sealing pipe threads (ISO 228). The tightness of threads that do not seal in the thread is achieved by sealing surfaces arranged outside the thread.
The most common pipe threads are those that seal in the thread; these are designed as cylindrical internal threads and tapered external threads with dimensional diameter overlap.
On the American continent, on the other hand, the US NPT(National Pipe Thread) is commonly used. In addition to the diameter coding, the dimension specification for NPT threads includes the number of thread turns per inch.
Because of the different number of threads per inch and minor differences in diameter, BSP and NPT threads cannot be completely screwed together. This can be seen when the thread cannot be screwed in at all or only a few (few) turns.
Examples of designations for threads that seal in the thread:
Designation examples for threads that do not seal in the thread:
(A, B for tolerance class).
External pipe threads are often also roughened - especially for brass parts - so that the hemp or sealing tape for sealing holds better in the thread when screwed in and does not shift when screwed in.
Excerpt from:
https://de.wikipedia.org/wiki/Gewinde
From today's perspective, the reference to inside diameter is rather obstructive and confusing:
- A 1″ pipe thread for medium-heavy threaded pipes does not have an outside diameter of 25.4 mm, but a range of 32.89 to 33.25 mm.
- High pressure pipes can also have a 1″ pipe thread, but due to the greater wall thickness, the inner diameter is smaller.
In Europe, the Whitworth thread is commonly used. It is also abbreviated to BSP (cylindrical thread) (British Standard Pipe).
According to the standard , a distinction is made between thread-sealing(EN 10226-1, previously: DIN 2999) and non-thread-sealing pipe threads (ISO 228). The tightness of threads that do not seal in the thread is achieved by sealing surfaces arranged outside the thread.
The most common pipe threads are those that seal in the thread; these are designed as cylindrical internal threads and tapered external threads with dimensional diameter overlap.
On the American continent, on the other hand, the US NPT(National Pipe Thread) is commonly used. In addition to the diameter coding, the dimension specification for NPT threads includes the number of thread turns per inch.
Because of the different number of threads per inch and minor differences in diameter, BSP and NPT threads cannot be completely screwed together. This can be seen when the thread cannot be screwed in at all or only a few (few) turns.
Examples of designations for threads that seal in the thread:
- for a tapered Whitworth external pipe thread: pipe thread DIN EN 10226-R½
- for a cylindrical Whitworth internal pipe thread: pipe thread DIN EN 10226-Rp½.
Designation examples for threads that do not seal in the thread:
- for a pipe internal thread: pipe thread ISO 228-G½
- for an external pipe thread: pipe thread ISO 228-G½ A
- for an external pipe thread: pipe thread ISO 228-G½ B
(A, B for tolerance class).
External pipe threads are often also roughened - especially for brass parts - so that the hemp or sealing tape for sealing holds better in the thread when screwed in and does not shift when screwed in.
Excerpt from:
https://de.wikipedia.org/wiki/Gewinde