Page:Popular Science Monthly Volume 46.djvu/628

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were now revolved the result would be a plain circle cut into the steel plate; or, if the oval slide which is built into the chuck is in operation, the result would be an oval (Fig. 12).

The several cams, when in use, cause the "beds" (of which there are two, laid on rollers) to move back and forth, or to the right and left, as the operator may desire, once for each revolution. Now, suppose one cam was geared to revolve eight times while the chuck is revolving once, we would then have eight

PSM V46 D628 Geometrical lathe.jpg
Fig. 11.—Geometrical Lathe. From "Paper and Press," by the kindness of W. M. Patton.

vibrations of the "bed," or eight waves in the line which was before a plain circle; therefore, we would now have an eight-sided figure, or a circle with eight bulges in it, (See inside line of the figure below.) If we now put another cam in motion, geared to revolve twenty-four times to the chuck once and the first cam's eight times, we would have twenty-four waves upon eight waves upon a circle, giving a line like that of the outside in the same figure (Fig. 13).

This has given us one of the many beautiful and perfectly geometrical forms that this wonderful and almost human machine is capable of producing under the management of a skilled artist.