It's always tricky drilling holes in wooden balls. You just can't quite get a good grip on them with a drill-press vise or clamp.

Make a simple set of auxiliary jaws that will give a vise or handscrew clamp a firm hold on wooden balls. Just cut two pieces of 34 "-thick stock (use pine or some other soft-textured wood) to fit your clamp or vise jaws (the ones shown above measure 2x4"). Then drill a 38 " hole through the center of each. Sandwich the ball between the holes, and place the assembly in the vise or clamp for a solid grip. If you have a lot of balls to bore, affix the auxiliary jaws to the clamp or vise with double-faced tape.
—Vincent Ferello, Sarasota, Fla.