A compact engine that draws power from a pneumatic surgical power tool system control unit intended to convert pneumatic energy [e.g., from surgical-grade air or nitrogen (N2)] into a non-dedicated mechanical energy to perform a variety of surgical procedures that include drilling, sawing, and inserting involving bones and tough tissues. It may be available in two different forms: 1) a pistol-like handpiece that connects to a variety of surgical power tool attachments; or 2) a proximal attachment (e.g., micro-motor) to a variety of motorless handpieces. The device may be cannulated to permit use of a guidewire. It may be operated with a hand- or foot-switch. This is a reusable device.