A helical compression spring is wound using 0.105-in-diameter music wire. The spring has an outside diameter of 1.225 in with plain ground ends, and 12 total coils.
(a) What should the free length be to ensure that when the spring is compressed solid the torsional stress does not exceed the yield strength, that is, that it is solid-safe?
(b) What force is needed to compress this spring to closure?
(c) Estimate the spring rate.
(d) Is there a possibility that the spring might buckle in service?