Turning Eccentrics in Three-Jaw Chuck

The Model Craftsman, February 1938

When you want to produce off-center work in your lathe, an independent, four-jaw chuck isn't altogether necessary. A three-jaw chuck will do the job just as well, as the darwing illustrates. Suppose you wish to make an eccentric, and have to drill or bore the hole in the center accurately. Measure the distance that the eccentric is to be off-center, then take a small block of brass and file it to this width. Select a piece of round stock of the correct outside diameter for the eccentric, and insert it in the chuck, using the brass block for a spacer.

See also Turning an Eccentric Hole in a 3-Jaw Chuck.