Screwing plywood pieces with drywall-type screws is quick and easy, but drilling holes in a straight line can be tricky. That’s why I made this handy little marking gauge that allows me to quickly and accurately mark a line on my plywood for drilling screw holes. To make it, simply cut a 3/8 in. by 3/8-in. rabbet into a board that is about 1-in. wide by 8-in. long. You now have a marking gauge to make a line that will put your screws exactly in the centered edge of your 3/4-in. plywood.