3M 933 Unitized wheel mandrel designed to attach a Scotch-Brite brand unitized wheel to a rotary tool. Small size enables access to small or intricate workpieces. 3M 933 Unitized wheel mandrel secures a small Scotch-Brite unitized sanding wheel to a rotary tool such as a die grinder for edge deburring and finishing applications. The flanges fit on either side of the wheel and are secured with the retainer nut.