Straight-Up Drill Guide - To bore a perfectly perpendicular hole, you need either a drill press or a couple of scraps of wood screwed together. The corner created by the scraps will steer the bit straight in every time. But if you’re looking for an excuse
Just a simple ruler stop. Made from beech and a modified brass nut. The magnet inside holds the ruler tight and ad some friction during precise setting. The last pic is a little tip: I added 2 magnets to my ruler.