How do I draw the spiral in an achimedean screw

[Pa Lamin]

Hi, Does anyone know how the spiral in an archimedean is drawn.
It is like a blade. Tried to use arc but setting the right UCS was a problem.
Tried rotating a circle, trimming when necessary and using ruled surfaces but to have circle around the body was another problem.
Can anyone help?
:roll:

[CADTutor]

I guess what you're after is a helix - oft asked question on this forum. Try using the Search facility and enter the word "helix".

Alternatively, see this topic (http://www.cadtutor.net/forum/viewtopic.php?t=1463)

[fuccaro]

Also you may try the HELSURF (http://cadtutor.net/forum/viewtopic.php?t=74) routine (scrol down on the page to find it)