For a recent project, I needed to drill accurately centered holes into some wooden balls I had purchased, so I came up with this jig to hold them securely on the drill press. To make the jig, first make the upper “clothespin” board from a short piece of stock whose thickness approaches the radius of the ball to be drilled. Cut a 1⁄4" slot in it, and screw it to a baseboard that’s long enough to span your drill press table. Then drill a hole through the upper board using a holesaw. (I used a Vermont American #18401 adjustable-diameter holesaw, which allows slight upsizing to accommodate the typical variance of wooden balls from their nominal diameters.)
To use the jig, first outfit your drill press with a standard twist bit whose diameter matches that of your holesaw’s pilot bit. Lower the bit into the pilot hole in the baseboard to center the jig under the drill chuck. After clamping the baseboard to the table in this position, switch out the bit with the one you’ll use to drill the ball, and pinch a ball in the jig by clamping across the slot. Now you’re ready to drill a perfectly centered hole.
