Occasionally, a plan calls for sawing a wooden ball in half. Such is the case for a rocking horse that uses two birch half-balls for eyes.

In one end of a length of 2x4, bore a hole 116 " smaller than the diameter of the ball and to a depth that's about three-fourths the diameter of the ball. Also, cut a kerf into the block as shown below, centered on the hole for the ball. Force the ball into the hole and cut. (Note: The ball must fit snugly into the jig to give you a safe, accurate cut.) Afterward, shut off the saw, allow the blade to stop, and remove the two halves.
—Henry E. Coleman, Anaheim, Calif.