It is rounded on one side, flat on the other Used on concave and convex as well as flat surfaces. The backs of all half round bastard files are double cut. The flat sides of all half files are double cut. The backs of all half round bastard files are double cut Drill America DIC series Qualtech American pattern bastard cut file is rounded on one side, flat on the other. Century Drill & Tool 4051 6 in. Mill File Bastard-Single Cut Half Round Bastard File 14 Inch 4" Half Round Double Cut Bastard File - Boxed 14 Inch Metal File File is used on concave and convex as well as flat surfaces The backs of all half round bastard files are double cut. The backs of all half round second cut files longer than 6 inches are double cut, the 4 and 6 inches files are single cut The flat sides of all half files are double cut. Used on concave and convex as well as flat surfaces.
