When I need holes drilled too far from the edge of a board to use my drill press, I reach for this handy drilling guide. It allows me to position the bit exactly and assures that I'll drill a perpendicular hole, as long as I hold the guide firmly on the workpiece. I can also drill to an accurate depth by chucking the drill bit so it protrudes beyond the guide by the depth of the hole I want to drill. Unlike stop collars that mount on the drill bit, this stop never mars the workpiece's surface. These guides are so handy, I've made them for many of my bits. First, using my drill press, I drill a perpendicular hole through the block. Then I cut the arch on my bandsaw.