exel die filer die filer made by exel british made as used by tool makers to back off dies and model engineers these take a special file made to fit them machine tool used in metalworking to file and shape metal parts. It is used to create precision cuts, surfaces, and contours on a workpiece. Die filers are commonly used in tool and die making, a field that involves designing and manufacturing tools, dies, and fixtures used in various manufacturing processes. dies for metal punching normally need a draft angle so the top is smaller than the bottom