Disclosed herein is a tool assembly for use with an energy applicator having a shaft extending along an axis between a proximal end and a distal end. The tool assembly comprises a support structure to support the energy applicator, and a connector assembly arranged to engage and releasably lock the energy applicator to the support structure in a locked state. A drive system is coupled to the support structure and is configured to rotatably drive the shaft of the energy applicator about the axis. The drive system comprises a counterweighted clutch assembly.