A Manual of the Hand Lathe / Comprising Concise Directions for Working Metals of All Kinds, Ivory, Bone and Precious Woods

by Egbert P. Watson

CENTERS.

An indispensable article on a foot lathe, where any fancy work is to be done, is the centers—of which I have before spoken—shown in [Fig. 46]. These consist of a common set of heads, with spindles fitted to them. One spindle has an index plate and spring, and the other has a common center. These heads set on a slide that is moved back and forth over a rest, screwed to the lathe bed as usual. It is easy to see that, with this, we can do some very fine cabinet work. Suppose we have a round vase turned up handsomely, and wish to flute the base or make it a series of curves all round; to do this, we have only to put it in the centers, set the index so as to come out even, as before explained, and go ahead.

Fig. 46.

The kind of cutter to be used is a sort of gouge, set in a cast-iron head, something as a plane iron is set in its stock. That is, fitted tight to a groove and held by a set screw. Two of these cutters should be used, at equal distances apart, and the cutter head should be keyed on a short shaft, set between the main centers of the lathe. The whole should be accurately balanced, or else the work will be full of chatters or ridges. Since centrifugal force increases as the square of the velocity, any thing that runs a little out of truth, will be very much exaggerated as the speed increases. By using cutters of different shapes, beautiful effects can be produced; as, for instance, suppose we take a common round-nose cutter, set the index so as to divide the circle of the job we are to work on in twenty-four parts, and execute that part of the design, then take a tool forming an ogee, and work out the spaces intervening, we shall find that the article, when completed, will have a beautiful appearance, and that, instead of being round, the bottom will be octagonal, which will present a pleasing contrast to the rest.

Fig. 47.

The centers can be set at any angle with the cutter shaft and a pineapple pattern can be made on straight surfaces, by executing one part at one angle, then reversing the rest that carries the centers, and finish the remainder, one part of the pattern crossing the other.

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.