Abstract: A portable grinder utilizing a standard electric hand drill as a source of mechanical power has a support base structure upon the upper surface of which is journalled a drive spindle one end of which is adapted to receive, in driving engagement, the chuck of the hand drill, and the other end of which serves to drive a grinding wheel and other rotatively driven tools selectively attachable thereto. Adjustable means is provided for supporting an electric hand drill in rotary alignment with the drive spindle; and a cover member removably attachable to the base structure renders the assemblage fully portable.