Table I.-Example Of Drawing German Silver Shell For Cartridge

Table II.-Example In Drawing Small Metal Sphere

first process, A, will be cutting and cupping the blank in combination tools; the second process, B, is a re-drawing process, or extending the previously cupped blank: the third process, C, is to part close the open end of the shell; and in the fourth process the shell is worked into a sphere by means of a special punch and die, which may be either called Killing tools or closing tools. Particulars of the dimensions at the various stages will be found in Table II.

Fig. 139.

Fig;. 140.

Fig. 141.

Fig. 142.

Another small shell, fig. 141, is drawn and headed. The particulars relating to this example are contained in Table III. The particulars that are given in Table IV. relate to the processes of drawing a small metal shell, but there is no drawing given to this example.

The complete processes of drawing and heading one form of cartridge shell are shown at fig. 142, and a study of Table V. will provide all particulars to enable the processes to be followed during the various stages. After cupping the blank the re-drawing, extending, lengthening, or deepening is carried out by a series of successive stages, at the same time reducing the diameter of the cup, or which we may now call a shell or tube, having one end closed. The number of stage's that are necessary for re-drawing or deepening a shell will greatly depend upon the condition of the metal when being worked. The action of the drawing tools tends to harden the metal, thereby making it necessary to anneal the article several times during the various stages through which the shell passes, to be formed into the long shell. The open end of the shell is afterwards reduced or closed by special reducing or closing tools. Work of this kind is frequently required to be tapered inside the shell; in other words, the metal of the shell to be thinner at the open end than near the head. This thinning of the metal will be brought about by making the drawing punch slightly taper. Then, during the drawing process, the punch being smaller in diameter for some distance from the end, will pass the shell through the die with comparatively little draw until it reaches the larger part or swell on the punch, when a flow of the metal will be brought about, resulting in the required reduction in thickness of the metal shell. The shape, both inside and outside drawn shells, is governed to a considerable extent by the shape or form of the drawing punch, both for its whole length and the end which enters the work for carrying it through the die. By increasing or decreasing the radius on the drawing corner of a punch a corresponding increase or decrease may be obtained at the corner of the article that is being drawn. But a point of