ok, now I understand. It's like lex2bits said, you aren't drilling your holes straight through the control surface. The best answer is to tell you to use a drill press when you drill your holes in the control surface. If you don't have a drill press you need to make sure you are drilling a perpendicular hole when you drill it. My best advice is to ask around at your flying field/club and see if you can find someone with a drill press. They can make you a guide fairly quickly so you can drill straight.