Here’s a guide for your brad or pin nailer that can help you drive nails in a straight line — and you’ve probably already got it in your desk drawer. Just attach a large paper binder clip to the bottom edge of your nail gun’s magazine. You can slide and position it anywhere along the bottom of the magazine to allow for various nailing distances. It’s got more than enough tension to stay in place and, while it does interfere with loading nail clips, it can be quickly and easily removed and repositioned.
– Jim Wilson
San Marcos, Texas