The Crescent Nicholson flat bastard file with an American pattern is ideal for machinists, machinery builders, ship and engine builders. The file 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 the slight taper in width towards the file's point creates ease of access in slots. Bastard cut, American pattern flat file. Ideal for machinists, machinery builders, ship and engine builders. Can be used effectively by repairmen and others who require rapid removal of metal. 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. Can be used effectively by repairmen and others who require rapid removal of metal.