In mechanical engineering, the thread angle of a screw is the included angle between the thread flanks, measured in a plane containing the thread axis.1 This is a defining factor for the shape of a screw thread. Standard values include:
| Name | Code | Angle | Profile | Standards |
|---|---|---|---|---|
| Most V-threads | M | 60° | 
|
including DIN 13 / ISO, NPT and UTS |
| Whitworth threads | W | 55°2 | 
|
DIN 49301 / BS |
| British standard pipe thread | G | 55° | 
|
DIN / BS / EN / ISO 228-1 / ISO 7-1 |
| National Pipe Thread | NPT | 60° | 
|
ASME B1.20.-1983 Pipe Threads, General Purpose, Inch |
|
Rd | 30° |  6
|
DIN 405 / DIN 20400 |
| Acme thread7 | 29° | 
|
ASME/ANSI B1.5-19888 | |
| Metric trapezoidal threads1 | Tr | 30° | 
|
DIN 103 |
| Buttress threads7 | S | 45° | 
|
DIN 2781 |
| German buttress threads7 | S | 30° | 
|
DIN 513 |
| Square threads1 | Sq | 0° (parallel) | 
|
? |
| Panzergewinde, "steel conduit thread" | Pg | 80° | 
|
DIN 40430 |
| British Association (BA) thread | BA | 47° 30' = 47.5° | 
|
BS 93:2008 |
| Löwenherz thread9 | 53° 8' ≈ 53.1° | |||
| Bodmer thread10 | 50° | |||
| Thury thread1112 | 47° 30' = 47.5° |
References
References
Notes
- Bhandari 2007, p. 203.
- BS 84: 1956
- Knuckle Thread DIN 405
- Knuckle Thread DIN 20400
- Bornemann
- Knuckle thread
- Bhandari 2007, p. 204.
- Machinery's Handbook (1996), pp. 1716.
- Löwenherz thread
- Bodmer thread
- Brooks, Randall C. "Standard Screw Threads for Scientific Instruments. Part 1: Production Techniques and the Filière Suisse." History and Technology, vol 5, 1988, pp. 68.
- Thury thread
Bibliography
- Bhandari, V B (2007), Design of Machine Elements, Tata McGraw-Hill, ISBN 978-0-07-061141-2.
- Oberg, Erik; Jones, Franklin D.; Horton, Holbrook L.; Ryffel, Henry H. (1996), Green, Robert E.; McCauley, Christopher J. (eds.), Machinery's Handbook (25th ed.), New York: Industrial Press, ISBN 978-0-8311-2575-2, OCLC 473691581.