A fraction of an inch can make the difference between a dowel hole that does the job and one that pokes through one edge at a mitered corner. To avoid problems, mark the center of a dowel and hold it in position over the joint. Reposition the dowel until you have at least 1⁄4
" of workpiece beyond each end of the dowel. Then mark the dowel location across the joint using a sharp pencil.
—from the WOOD® shop