Bending dies are simple when the metal is bent at a single angle, and complex when a loop is required. Its in making armature connections, switchboa rd:4. and the like. D•an•i»g dies are dies which are used for 'drawing lip or shaping metal into sitell forms as basins. thimble;, and hells. In some complex dies the metal is shaped, stamped with a design, and cut, all lay a single stroke of the press. as in making black ing-box covers. Very often. however. in pro diming the more complicated forms of drawn work, the object is put through several dies it attains its completed shape. The crank of an ordinary bicycle has to pass through a dozen or more presses before the flat sheet of is transformed into the piece of complicated tubing remiin-d. But even then the pieeess of cutting and bending cold steel by means of power-driven (lies is much less ex p( mice than the old method of forging such parts roughly into shape. drilling out the eavi ti.s, and turning and polishing the surfaces.
onsidering now the Ilse of dies for stamping figures oil metallic surfaces. its coins and medals, It is found that the preliminary puneess of die -inking is an elalmrat• one. It requires great skill and gives opportunity for the display of artistic- feeling and talent as well. Die-•inking is a branch of engraving, but it. involves the use of other tools besides those of the engraver. A
piece of softened steel, called the hub, is pre paed, and on its cud the design is cut. The steel is tlien hardened and forms the matrix. The design mu lire matrix is impressed upon another plug of softened steel, with the result that the design. wrought in intaglio on the ma trix, collies out in relief on the second piece of metal. which is called the punch. The punch, ill turn. is hardened and used to impress the design upon a third piece of metal. This third piece is of emirse an exact duplieate of the matrix and forms the die to be used for stamp mg coins. 'pie original matrix upon which the design was engraved is not used for stamping (•itus, because the expense of engraving is very j_reat, and the life of a die is short, hut is saved for making more dies. One step in the process outlined may he saved by engraving the design, in relief, in the first place so that the punch made from this design in intaglio can lie used as a (lie for coining or stamping.
Consult: Luca:, Dies and Flit- linking ( &nee, IL 1,, 1897 ),:t pr:kel iral t rent ise on t he subject of making (lies for inamifileturing purposes: and Woodwort h. Dies I New York, 1902 - The art kb- by Oberlin Smith, alluded to in the text, contains an admirable of the results obtained by this method of metalworking. See also article AUNT.