Thread angle
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 (including ISO, NPT and UTS) |
M | 60° | ![]() |
DIN 13 / ISO ? / ASME/ANSI ? |
Whitworth threads | W | 55° | ![]() |
DIN 49301 / BS ? |
G | 55° | ![]() |
DIN / BS / EN / ISO 228-1 / ISO 7-1 | |
Pipe thread
National Pipe Thread |
NPT | 60 | see wikipedia page on
NPT threads as I can't upload a profile drawing from another wikipedia page |
ASME B1.20.-1983 Pipe Threads, General Purpose, Inch |
|
Rd | 30° | ![]() |
DIN 405 / DIN 20400 |
Acme thread[6] | 29° | ![]() |
ASME/ANSI B1.5-1988[7] | |
Metric trapezoidal threads[1] | Tr | 30° | ![]() |
DIN 103 |
Buttress threads[6] | S | 45° | ![]() |
DIN 2781 |
German buttress threads[6] | S | 30° | ![]() |
DIN 513 |
Square threads[1] | Sq | 0° | ![]() |
? |
|
Pg | 80° | ![]() |
DIN 40430 |
British Association (BA) thread | BA |
|
? | BS 93:2008 |
Löwenherz thread[8] | ? |
|
? | ? |
Bodmer thread[9] | ? | 50° | ? | ? |
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Diagram of a thread angle
References
Notes
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.
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