Help modeling a spiral extrude

[Rostislav_SE]

Hello!
I am trying (without succes) to draw a spiral on a surface and then cut (extrude) it out...

Any tips on how to draw it the easiest way possible?

I draw a pic (sorry for quality. Paint

) that may help to explain what I mean.

The thickness of the spiral curve should be about 5mm or so.

 

[dr_gallup]

Use a datum curve from equation with a cylindrical csys:

/* For cylindrical coordinate system, enter parametric equation
/* in terms of t (which will vary from 0 to 1) for r, theta and z
/* For example: for a circle in x-y plane, centered at origin
/* and radius = 4, the parametric equations will be:
/*&nbs p; r = 4
/* theta = t * 360
/*&nbs p; z = 0
/*---------------------------------------------------------- ---------
Z=0
R=.5+theta/100
Theta=t*5*360