For indexing, it will be noted that the top of the wooden block is divided into eight parts with pencil-marks. These can be used as starting-points for any type of cut with various types of cutters, depending on the design desired. In this case, the tool is pivoted by hand thru the length of the cut, and the same cut repeated eight times, turning the face-plate one-eighth of a turn, making a cut once at each pencil-mark.
Figure 13 and Plate 2B shows the same principle applied in straight lines, to rabbet shoulders or grooves in box-lids, etc. The two pieces of wood, which are "bed" and "guide" respectively, are tacked to the bench (or to a drawing-board), the tool with the proper cutter held firmly in the hand, shimmed up to the correct height, and the sheet of plastic shoved slowly under the cutter with the other hand.
Figure 13 (lower) goes still further, and uses the cylinder to provide the movement. Here a bracelet-cylinder is shown, resting in a cradle consisting of five nails driven in the bench, two on each side, and one at the tail, all making contact with the cylinder. It is obvious that if the cylinder is slowly turned by hand, held down firmly to the bench with one hand, while the other hand holds the hand-grinder in which is mounted a small saw-blade or abrasive cut-off wheel, bracelet-rings can be cut from the cylinder that are just as true as those cut on the lathe. Further acquaintance with these handy little machines will reveal many other simple set-ups that will save a lot of time, labor or permit the accomplishment of operations which would otherwise been impossible.
Spindle-Carving The next step up in equipment is spindle-carving. A spindle carver consists of a rotating spindle which projects about 6" or 8" from the bearings, on the end of which cutters are mounted, and this is the most common and most convenient for the majority of carving operations. Here again there is wide latitude, and no matter how limited your power-tool equipment, it is possible to rig up something that will work very well. First we will describe various methods of approaching the subject from the homeworkshop standpoint, and then describe professional equipment, the best of which only costs twenty-five dollars or so, with a complete set of cutters and arbors costing about as much more.
One of the handiest and least expensive home-made gadgets for power carving is a little motor with a long spindle, with cutters mounted on the end of the spindle. In New York, and probably all over the country, the second-hand electrical dealers always have a few small motors, (1/40th to 1/10 th H.P.) from old phonographs or dictaphones which can be had for a dollar or two, and which have spindles which project from 3" to 4" from the motor-frame. These are usually high-speed motors, some of them good for 5000 R.P.M. By holding a file on the spindle, it is possible to turn down a shoulder about 1/2" long, which can be threaded with a die to 10/32 or a larger thread if the spindle-diameter will permit it, and which makes a very good cutter-arbor. As to cutters, these can be made without any power-tools whatever if need be, from brass or hard bronze washers, 1/2" or more in diameter, drilled and tapped to fit this thread in the center, and with notches filed around the edge. These notches need be neither very deep or particularly uniform, the only requirement being that the front edge of the teeth so formed should be on a straight line toward the center of the washer. Before cutting the teeth, incidentally, the washer can be trued concentric, and its edge shaped (square, rounded or pointed) by holding the file against them while the motor is running. A little "relief" should also be filed in the back of the cutting edge, of each tooth as indicated in Figure 14. This carving device is not very powerful, to be sure, and there is not room enough between the cutter and the motor-frame to handle large sheets and other objects, but for rings and such work there is absolutely no reason why work cannot be turned out on it that is comparable to any work of similar size on the market, if your cutters are kept fairly sharp. Moreover, such an outfit shown in Plate 2C is light in weight, portable and quiet, and can be used anywhere in the house—I know of one being used in occupational therapy work in a hospital, for instance, the thing being set on a tray in the patients' beds.
Fig. 14. The proper shape for hand-filed carving-cutter teeth — a straight front and a slight relief in back.
If the motor has a double spindle and you are able to rig up an arbor for the other end to hold a small grinding-wheel, or buffer or sanding-disc it becomes a complete workshop in itself. If you have a lathe as well, whether it is wood or metal-working, the making of the cutters is greatly simplified and you should make up a complete set of various shapes and sizes.