Use dowel centers to find centers of dowels
First, in a piece of 3⁄4 "-thick stock, use Forstner bits to drill a series of 3⁄8 "-deep holes that match the size of your dowels. Drill a centered 1⁄4 " hole through the dimple made by the Forstner bit's center point.
To use the jig, insert a 1⁄4 " dowel center (no. 42341, for an 8-pack, 800-279-4441, rockler.com) in each hole, point up. Fit the end of a dowel into the appropriate-sized hole and press the dowel into the jig or tap it with a mallet. The resulting dimple clearly marks the dowel's center.
—Len Urban, Rancho Mirage, Calif.