I present here views of a novel ornament which exhibits great mechanical ingenuity and manual dexterity, but is otherwise of no value. It consists, in one form, of a globe with a series of rings or globes inside, and a six-armed spur projecting through holes—all cut out of one solid piece. Fig. 47.
Fig. 48 shows how the points are turned. After the internal rings are cut out with a quadrant tool like Fig. 49, and the spur also severed, by cutting in the ends of the holes (not boring them out solid), the globe is put in a shell chuck, with three set screws in it, as shown. The set screws go through the holes in the globe, and the cross pieces, in between the spurs, serve to steady the job. Any number of points may be turned in the globe. Fig. 50 shows a polygon with many spurs turned inside. At first sight it would appear that the tool, severing the rings, would cut off the points also, but it will be seen that this is not the case, for the holes being bored so as to leave a core standing (which afterward serves to make the points of the spur), the severing tool falls into the holes and goes no further, and each division serves as a guide for the tool in the next hole, so that the globe is made the same size, without jags. The quadrant tool, shown before, must be followed round the shell in the act of cutting it out, so that it will make the same round, and the globe must be shifted in the chuck, to reach all the holes. It is no easy task to make this little affair, for all it looks so simple.
Fig. 51 is another, a little more ornate and of a different pattern. The process is essentially the same, except that there are no spurs and a solid disk is left inside. This disk is turned out of a ball, left inside the exterior shell. One side of it is squared up before the ball is cut free from the globe, and the job is then reversed and the other side squared. The ball is then cut free, and the loose disk is held fast between a flat-ended driver in the live spindle, and a loose, flat-ended button on the back center. The diameter is then decided through the hole which is toward the reader.
A little tool, which is very convenient for making small screws, is here shown in Fig. 52, rather out of place, but it was overlooked before. In construction it explains itself. Holes of different sizes are made in a steel rod, and the end filed into shape, as seen. It has been found difficult by some to make these cutters work, but that was because they were not properly made. The trouble lies in drilling the hole. When the drill starts at first, the hole is larger on the outside, so that the screw blank, when cut, gets tighter as it goes in, and twists it off.