• For 1″ To 1 1/2″ interior diameter bores • 60 grit • For sizing and blending out medium machine marks • Use with Bpm-4 mandrel part no. 08834154183 • Extension mandrels are available • For deep holes • 4 Abrasive packs 1-1/2 In. wide, bonded to hub • Bore polishers are used • For deburring, cleaning and polishing of the interior diameters of cylinders, tubes and hydraulic fittings. The flaps automatically adjust to the inside diameter, polishing the entire surface with one pass. A self-centering, spring action design gives a fast and easy way to handle all inside diameter jobs.