NACHI HIGH SPEED STEEL TWIST DRILL.N500~N602~N6520~N6602 Description NACHI DRILLS. N500 HIGH SPEED STEEL TWIST DRILL. N6520 COBALT HIGH SPEED STEEL TOUGH DRILLS, STRAIGHT SHANK N602 HIGH SPEED STEEL TWIST DRILLS, TAPER SHANK N6602 COBALT HIGH SPEED STEEL TOUGH DRILLS, TAPER SHANK View More Details