Originally Posted By: 2-piper
As I see it the action of a coil spring is probably a combination of beam & torion but more beam than torsion.


Please do not take this as an insult, but the way you see it is not only incorrect but also impossible. All coil springs, be they tension or compression type, experience ONLY torsion during compression or extension. The laws of physics are quite immutable and the operation of coil springs isn't debatable or open to interpretation.

The diagram shows a part of a compression spring that supports a compressive load P and a section of the wire cut by axial plane. The part of spring shown in the figure is in equilibrium under the action of the two forces P and resisting torsional moment T.