The Crescent Nicholson 6" flat file with a bastard cut is a tool designed for rapid removal of metal. It's an American pattern flat file, ideal for machinists, machinery builders, and engine builders. The file is double cut on the sides and single cut on the edges, which allows for both rough filing and a smoother finish. It's rectangular in cross-section and tapers slightly towards the point in width, making it suitable for a variety of tasks including sharpening and smoothing straight surfaces.