Hi Al,
impressive nod thanks for sharing. The problem in question is the pitch of the helix must be equal around the curve but at the moment the pitch is equal over it's length. In the attach gif for 1 revolution of the cam the
roller moves 20 degrees. Perhaps a nod could plot the points required to produce the helix or do a Boolean difference every step to get the basic shape. I have produced a nod to do the basic movements but now stuck on best way to go ie:boolean or points any help would be great.
This maybe of interest. https://archivesmse.org/api/files/view/122245.pdf
Barry
Ps Added new gif manually created helix on hour glass shape.