I do it by placing a 60 deg pointed rod, point up in the drill press vise. Then the vise is positioned so that a drill in the chuck meets the rod point dead center and coaxial. Center drill the screw locations just enough to provide a good seat for the rod point.

Using a sharp brad-point drill, place the stock in position on the rod point, hold it firmly, and drill it. The drill will cut until you hit the rod point, so be gentle with the quill handle as you approach full depth.

OB