The bottom of the fuselage on the Simple Scout runs at an angle to the tail. So when cutting the balsa sticks the bottom needs to be cut at the same angle. The top of the stick is square, so no need to cut an angle. I made this cutting guide from a couple pieces of scrap foam board and one piece of 3/16″x3/16″ balsa stick. Just make your mark, then cut or sand the stick and glue it in place. Works really well to give you nice tight joints.