The cross section profile of a diamond parting tool allows it to make deep parting cuts without binding in the cut. With a narrow cutting edge required to make deep plunging cuts, it needs to be tough. This parting tool has a cryogenically hardened M42 tool steel blade. The M42 steel gives you a tool with unrivalled edge retention and the ultimate tool life. M42 is a premium, high-speed steel alloy with molybdenum and 8% cobalt. One of its most significant properties is high wear resistance. The cutting edges on tools made from M42 high-speed steel stay sharp and hard in heavy-duty and high-production applications. Common uses of M42 include twist drills, milling cutters, reamers, broaches, saws and thread rolling dies. When it comes to woodturning tools, you have a tool that will hold an edge far longer than any other, even on tough and abrasive timbers.