D108 Jobber Drills Heavy Duty Cobalt Sutton Tools Heavy Duty Cobalt jobber drills are industrial quality for drilling materials that have high hardness and tensile strength such as cast iron, bronze, hardened steel & stainless steel. These drill bits feature a thick core for increased rigidity in hard materials. 135 split point (drills > 2mm & 3/32) enables accurate positioning and less drilling pressure Thick core for increased rigidity in hard materials Precision engineered parallel shank for accurate hole size Made from HSS Co. The 5% cobalt formula improves abrasive & heat resistance, for increased strength at higher cutting temperatures Colour Tempered surface finish enables identification of cobalt tool material Diameter 7.94mm / 5/16 Flute Length 81mm Length 114mm