Nicholson 8" Black Diamond Flat Bastard File is a high carbon steel file with a rectangular cross section and a double cut on the sides with single cuts on the edges. It is used to rapidly remove metal and has an American pattern. The Crescent® Nicholson flat double/single-cut bastard filees with an American pattern are ideal for machinists, machinery builders, ship and engine builders. The files can be used effectively by repairmen and others who require rapid removal of metal. The rectangular cross section allows you to smooth and sharpen straight surfaces, while slight taper in width towards the file's point creates ease of access in slots.