These specialty rods are designed to remove the hard to reach burrs created by cross-drilled holes. Available if 4 shapes: Oval, Cross, Ring, and Thin, and a variety of diameters for different cross hole sizes and shapes. The cutting wires are made from a slightly flexible, twisted piano wire and measure approx. 0.027” in wire diameter. The wires are more aggressive than brushes, yet less aggressive than traditional cutting burs. These deburring rods work best on harder metals such as steel. Recommended for use in a rotary power tool. 3mm shank diameter. 1,000 Max RPM. All rods measure 4” in OAL.