Chisels

Abstract

A point chisel includes a substantially cylindrical shank and a working end region that tapers to a point. The working end region has at least three converging substantially planar surfaces, each with a protruding elongate rib extending along at least part of its length. Adjacent surfaces meet along at least part of their length at substantially straight edges between adjacent ribs. A flat chisel includes a substantially cylindrical shank and a working end region with a pair of converging substantially planar surfaces that include a plurality of protruding elongate ribs extending along at least part of its length. Each rib has, along the majority of its length, a substantially constant height above the surface from which it protrudes. Each chisel is made from steel, with the shank having a bainitic microstructure and the working end region having a martensitic microstructure.

Dependencies are inferred from the claim text.