Thread angle
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. 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 ? | |
| 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° | DIN 405 / DIN 20400 | |
| Acme thread | 29° | ASME/ANSI B1.5-1988 | ||
| Metric trapezoidal threads | Tr | 30° | DIN 103 | |
| Buttress threads | S | 45° | DIN 2781 | |
| German buttress threads | S | 30° | DIN 513 | |
| Square threads | Sq | 0° (parallel) | ? | |
| Panzergewinde, "steel conduit thread" | Pg | 80° | DIN 40430 | |
| British Association (BA) thread | BA | 47° 30' = 47.5° | BS 93:2008 | |
| Löwenherz thread | 53° 8' ≈ 53.1° | |||
| Bodmer thread | 50° |
