This is a simple and very accurate jig for drilling holes at a precise offset from any given corner. By using three drill bits of varying sizes, it's easy to precisely control the spacing of the corner hole for dead-on accuracy.

The key is to drill the first hole against the drill press fence, then rotate 90° with the drill bit still in the work piece. Setting a stop block against the rotated edge gives you a perfect corner offset in both directions.

Then, use two drill bits (the same size as the hole) with a third bit across them to act as a precise spacer.