In making models of machinery or toy machines, cams are very often required. A simple way of making these is to lay out the cam plate, or drum, and then bend pieces of brass to the correct shape and solder them in place, whereupon they may be smoothed up with a file or scraper. A cam of this sort on a drum is shown in the sketch at A, and on a faceplate, at B. The method is not quite as accurate as milling, but answers the purpose in most cases. - Contributed by Chas. Hatten-berger, Buffalo, N. Y.

Ill: Channels of the Cams Formed with Strips of Brass Soldered to the Drum or Disk