Spin two nuts onto the bolt, tightening them against each other. Then chuck the bolt into the drill and hold a hacksaw blade against the spinning bolt. The nuts help to steady the blade and clean off burrs when you unscrew them.
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