At Solidworks World, Robert McDonald showed a really terrific sample animation of a compression spring. I made the mistake of commenting that, for the sake of an animation, it is rough to use a helical sweep feature to make the spring because you take a beating on the rebuild time, and that techniques existed using simple, fast-rebuilding revolves to simulate a spring (at least well-enough to serve an animation)
Big mistake - next thing I know, I have a handful of people handing me business cards so I could send them a sample model.
The links below will allow you to download the compression spring, and an extension and torsion spring I had laying around. The models are for education on modeling strategy only - I did not look up any springs for real, nor did I take a ton of time to clean up the models the way I would if I was doing them for a customer/delivering to a customer.
By the way, the compression spring is kind of cool because it shows a trick for getting equations to evalaute betwen frames in an animation. I needed the spring to be equation driven so anyone could use it to add coils, change diameter, etc without doing a lot of reconstruction. The spring I did a few years ago used equal sketch relations to flex the spring, so it would be a lot of work to make any cahnge. I figured I ought to beat the limitation if I was going to share it.
-Ed