Step Tip Drill 4-32mm Co5 TiAlN 3-Flat Round Shank HSS-Co5 (Cobalt) Titanium Aluminium Nitride Coated (TiAlN) step drills offer unparalleled performance when drilling hard metals such as stainless steel. Step Tip negates the need for a pilot drill in metals and provides extreme drilling speeds in ferrous and non-ferrous metals, plastic and all timbers. Laser marked diameters on each step for fast identification. HSS-Co5 material provides increased performance and tool life when machining tough steels. Bordo step drills are ideal for electrical contractors, sheetmetal workers and auto mechanics. Step drills are designed for drilling repetitive holes in steel, stainless steel, copper, brass, aluminium, plastic, plexiglas, laminates and many other materials. Automatic deburring. Spiral flutes enable easier tool penetration. Titanium Aluminium Nitride (TiAlN) is a thin film coating that was developed from Titanium Nitride. TiAlN offers higher temperature resistance than TiN, as well as slightly higher hardness and especially higher hot hardness (i.e. the hardness at high temperatures). It is primarily used in high temperature environments above the limits of TiN usage. This coating works by forming a thin surface layer of Alumina (Al2O3), or Aluminium Oxide ceramic. As the layer wears it continuously reforms.