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:

Thread standard Thread angle Profile Letter code Standards
Most V-threads
(including ISO, NPT and UTS)
60° M DIN 13 / ISO ? / ASME/ANSI ?
Whitworth threads 55° W DIN 49301 / BS ?
Pipe thread
British standard pipe thread
55° G DIN / BS / EN / ISO 228-1 / ISO 7-1
Knuckle thread / round thread[2][3][4] 30° [5] Rd DIN 405 / DIN 20400
Acme thread[6] 29° ? ASME/ANSI B1.5-1988[7]
Metric trapezoidal threads[1] 30° Tr DIN 103
Buttress threads[6] 45° S DIN 2781
German Buttress threads[6] 30° S DIN 513
Square threads[1] Sq ?
Steel conduit thread
aka Panzergewinde
80° Pg DIN 40430
Löwenherz thread[8] 53° 8' ? ? ?
Bodmer thread [9] 50° ? ? ?

References

Notes

Bibliography