Get dead-on straight edges with a router
Good glue joints require dead-straight surfaces, so if you can’t rip board edges straight enough, try this trick. Using a piece of quality plywood, clamp its factory-straight edge to within about 1⁄16 " of the workpiece’s sawn edge, as shown. Outfit your router with a flush-trim bit with a cutting edge at least 1" long. With the bearing riding against the plywood, rout the board flush for a glue-ready edge.