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, hard steel & stainless steel. These drill bits feature a thick core for increased rigidity in hard materials.
Sutton Tools Blue Bullet jobber drills are a general purpose drill bit designed for machine and hand held drilling ferrous metals. The blue finish reduces chip build up on the cutting edge and is a better choice when drilling ferrous materials.