DescriptionGRAFF drill bits, Set of 10 are made of HSS steel by rolling (screw-rolling) method with ground edge according to DIN338 standard. Drill bits have a cylindrical shank for a drill. Angle at the apex of 135 degrees and cross undercutting provide excellent drilling of metal without pre-drilling. Drill bits are used for drilling bores in alloyed and unalloyed steels, malleable and gray cast iron. Diameter, mm Totallength, mm Workingpart, mm Recommended rotationsper minute, rpm 1 34 12 5740 2 49 24 4780 3 61 33 3820 4 75 43 2870 5 86 52 1910 6 93 57 1720 7 109 69 1530 8 117 75 1340 9 125 81 1150 10 133 87 960
