Modeling a ball gear I'm trying to model a ball gear (not a worm gear) in blender, like the one in this picture. 



I have tried using the worm gear from the extra objects add on, but I can't get it to look right. Can anyone give me some tips?

Here is what I have been able to make so far:
Consider a Curve Modifier and Array.
Similar to winding cable around a spindle.






Curve Above.





Mesh Component Selected.  Modifiers Array and Curve.