What is "thread angle"

The thread angle of a screw is the angle between the threads. 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°

Spitzgewinde.jpg

DIN 13 / ISO ? / ASME/ ANSI ?

Whitworth threads

W

55°

Whitworth-Gewinde.jpg

DIN 49301 / BS ?

G

55°

Rohrgewinde.jpg

DIN / BS / EN / ISO 228-1 / ISO 7-1

Rd

30°

DIN 405 / DIN 20400

Acme thread

29°

Acme thread.svg

ASME/ANSI B1.5-1988

Metric trapezoidal threads

Tr

30°

Trapezgewinde 2.jpg

DIN 103

Buttress threads

S

45°

Buttress thread form.svg

DIN 2781

German buttress threads

S

30°

Saegengewindeprofil.jpg

DIN 513

Square threads

Sq

0°

Flachgewinde.jpg

?

Pg

80°

Stahlpanzerrohrgewinde.jpg

DIN 40430

British Association (BA) thread

BA

?

BS 93:2008

Löwenherz thread

?

?

?

Bodmer thread

?

50°

?

?