General-purpose drills for light duty work, for drilling steels, cast iron, nickel brass and graphite. Reduced parallel shank 1/2". Point angle 118¡ã, helix angle: normal, web thickness: standard, tolerance of diameter: h8, tolerance of shank: -0.01/0.08. Manufactured to BS328. Fracturing of the drill shank may occur if it is used for any other purpose or if extreme pressure is exerted on the drill.