SQUARE file, Round file, Half-round file, TRIANGULAR file, and Knife-edge file.Flat file: These files are USED for general purpose work. They are useful for filing and finishing external and internal surfaces.Hand file: They are useful for filing surfaces which are at right angles to surfaces already finished.Square File: It is used for filing square holes, internal square corners, rectangular OPENINGS, keyways, and splines.Round file: It is used for enlarging the circular holes and filing PROFILES with fillets.Half-round file: A half-round file is in the shape of a segment of a circle. It is used for filing internal curved surfaces.Knife-edge file: It is used for filing narrow grooves and angles above 10°.Triangular file: It is used for filing corners and angles which are more than 60°.