B208SM400 - Double Cut Carbide Burs Cone Shape 1/4? Shank Cone Shape Carbide Burs The chisel tooth pattern not only minimises tool chatter but reduces the chip to a granular shape, in most materials. Al Cut for rapid material removal of soft materials such as: Aluminium, Brass, Copper, Plastics that would normally load other cuts Shank 1/4 Length 2 1/2 / 63.5mm Diameter of Head 3/8/9.6mm Length of Head 3/4 / 19mm