Every mechanic knows how nice and rapidly a well-made drill will cut. Suppose this form of cutting edge be applied to the bullet cherry. It is no matter if this cherry be round or of conical form. Fill two cutting edges like a drill on opposite sides of the blank from the shank to the end of the cherry. It is evident that here the two rounded portions that are left on each side of the cutting edges to be removed that the tool is nothing more nor less than a peculiar shaped drill or reamer that might form an internal sphere. But as this form could not well be applied between the sides of blank bullet moulds, and as the full rounded sides would not permit of these edges cutting, then form the rounded surfaces into similar cutting edges like the two first made, only not so large, making three or four on each side, according to the size of the cherry. These cuts can very easily be made with a fine cut three-square or half-round file. A cherry of this form for a round ball is shown in Fig. 70, and one for a conical ball in Fig. 71. [Illustration: FIGURE 70.] [Illustration: FIGURE 71.] In using a three-square file, to get a fine-cutting edge that will make a sharp V cut, grind away the teeth of one side. This will remove the slightly rounded or blunt edge as usually made on this form of file. By grinding thus, two acute cutting angles can be had from one file. If they get a little dull on the sharp cutting corner, a little grinding will restore the edge and make it sharp again. _Tempering Bullet Cherries._—In tempering the cherry do not leave it too hard, and be careful not to temper too hard above the spherical portion. Leave the shank softer, as it will be less liable to break. It is not necessary to shape the shank so as to exactly conform to the shape of the V opening in the forming tool, for, as the edges of this opening have been bevelled the same as the opening that shapes the cherry, they will act as cutters, and will reduce the shank to conform to the V. It is well to mark the cherries in some conspicuous place on the shank, with their size in hundredths of an inch, the same as cartridges are numbered, and also mark them with the number of round balls to the pound, as was formerly in vogue among gunsmiths. The finished cherries, as purchased from dealers, are so numbered. Cherries, as purchased, have shanks fitted to be used with a bit-stock, but if the gunsmith fits these tools to be used in a lathe chuck that has a round hole, necessitating a round shank, and also wishes to use them in a bit-stock, he can fill up the square hole in the bit-stock by brazing therein a piece of iron, and then drilling a round hole to fit the tool. CHAPTER XXVIII. SCREW-MAKING TOOLS.