Applied -- Spring Fatigue

Given: A spring supports a minimum force of 60 lbf and a max force of 150 lbf while deflecting 1.0 in. A 10 year life of 1-shift per day operation is desired.

Required: Design a compression spring to suit this situation.

Assumptions: A228 music wire is used. Spring will be shot peened. Will start design with d=.207 in.