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.
Here's an oldie with a twist. Use pieces of garden hose or other tubing to soften the jaws of slip-joint or other pliers so you can grip plated surfaces without damage. The twist? Size them so you can slide them up the handles to keep them handy.
How to Build a Simple Circular Saw Guide for Straighter Cuts