Here’s an easy-to-make jig to have on hand for marking the center points of common dowel sizes. Take a block of scrap and drill a shallow hole in it for every dowel diameter you use. Bore these holes with Forstner or brad-point bits so the center spur of the bit marks the bottom of the hole. Now drill a tiny pilot hole at these marks all the way down through the block, and insert a brad nail into each pilot hole with its point facing up. Choose nails that will protrude about 1/8″ into the dowel holes. Then, to find a dowel’s center point, simply insert it into the matching hole in the jig, push down and twist to prick the end.
– Mel Johansen