MR-80A 3-80mm Universal Big Drill Bit Grinder, Grinding Machine The MR-80A drill grinder can grind various kinds of drills, such as standard twist drill, bottoming drills, multiple diameter drills, 2-four fact drills, masonry drills,wood drills, end mills, spot facer, and all kinds of flank, rake face, chisel edge and chamfering of point angle drills.