Creating a helical feed screw

[robertK8XQU]

Hello,

I'm trying to re-create this object in Fusion 360 and i'm completely clueless where to begin. It is a vertical feed screw for marbles to travel up. I've tried using the coil tool but i can't get that nice double helix shape.

Any pointers on how I can achieve this?

Thank you!

[etfrench · Accepted solution]

Start with a coil with a circular section size of  your marbles (plus a little clearance):

Model a cylinder with the major diameter of the desired thread:

Combine/Cut the coil from the cylinder(The cylinder must be longer than the coil).  Trim the ends.

[robertK8XQU]

Thank you!