Drill America DWD29J-CO-PC Cobalt Jobber Drill Bit Set. Set of 29 jobber length drill bits includes inch sizes 1/16″ to 1/2″ in 1/64 increments. Cobalt steel provides extended tool life compared to high-speed steel drill bits when drilling hard materials. Gold oxide finish lubricates the drill bit and provides wear resistance. Self-centering 135-degree split point penetrates hard material without a pilot hole and produces small chips to reduce clogging. Brand : Drill America. Type: Drill Bit.