A surgical rotary cutting tool and guard assembly is provided in which the cutting tool has a shaft with a proximal end and a distal end with an end effector at the distal end. The shaft includes at least one bearing mounted thereto intermediate the proximal and distal ends, the bearing having an inside dimension and the shaft having an outside dimension that provide for an interference fit between the bearing and the shaft. A tubular sleeve that serves as a guard houses the shaft, the sleeve having an inside dimension sized to slidably support the bearing.