Mike J Wilson - Consider the date!

I use equations with spring helices all the time.

All you need to do is double-click the helix in the feature manager tree and the dimensions appear like any other feature.

I find it helpful to first rename all of the spring dimensions so that I'm sure I have the right ones when I'm picking them for equations.

Hmmm... Thanks for the reply.

I must be doing something fundamentally wrong. I'm creating a circle and then invoking the Insert/Curve/Helix-Spiral command. I then Sweep a circular sketch along this spiral to create the spring. I cannot for the life of me assign a height to the spiral using a dimension. Any idea where I'm going wrong?

GC

Yep. I know what's wrong.

Helix is a funny creature that only likes to be used once and forgotten. Once you use it in a feature, the endpoints can't be referenced to make planes. Perhaps this time it has also decided not to be available for equations.

Roll back to before your helical sweep and create a temporary guide curve to replace the one in your sweep. Edit your sweep so it's not using the helix anymore, and then try to access the helix's parameters.

When I make spring coils, I copy the helix into a 3D sketch and use that in the sweep, due to the reasons mentioned above.

I have a torsion spring model you might want to see. It's available at . It's not an extension spring, but you can still see how to link spring parameters to equations.