In this work we present a novel control design methodology for under-actuated mechanical systems. As part of the design process we use the reachability analysis tool d/dt [ABDM99,D00] to see whether there is a switching sequence which can drive the system to a desired periodic orbit. Much of the work in the design of the control law is done manually using classical control techniques (unlike the fully-automatic approach advocated in [ABD+ 00]), and d/dt is used to complement these techniques. We hope this work will contribute to the proliferation of reachability-based techniques to the control engineer’s tool box.