Thread angle

Diagram of a thread angle

The thread angle of a screw is the angle between the threads.^[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 ?
Pipe thread British standard pipe thread	G	55°		DIN / BS / EN / ISO 228-1 / ISO 7-1
Knuckle thread[2][3][4] Round thread	Rd	30°	[5]	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°		?
Steel conduit thread Panzergewinde	Pg	80°		DIN 40430
British Association (BA) thread	BA	47° 30'	?	BS 93:2008
Löwenherz thread[8]	?	53° 8' (53.1°)	?	?
Bodmer thread[9]	?	50°	?	?

References

Notes

1. Bhandari 2007, p. 203.
2. Knuckle Thread DIN 405
3. Knuckle Thread DIN 20400
4. Bornemann
5. Knuckle thread
6. Bhandari 2007, p. 204.
7. Green 1996, p. 1716.
8. Löwenherz thread
9. Bodmer 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, NY, USA: Industrial Press, ISBN 978-0-8311-2575-2, OCLC 473691581.