What is a bastard file?

A bastard file is a type of flat file used for shaping and smoothing metal surfaces. It has a coarse double-cut on one face and a finer single-cut on the other, making it ideal for both rough shaping and finishing work. The term "bastard" refers to the file's in-between coarseness, which falls between a rough file and a smooth file. Bastard files are commonly used in metalworking, woodworking, and other trades that require precise shaping and finishing of materials. They are typically available in various sizes and shapes to suit different applications.