The star washers are a great idea for aluminum I believe they make lock Tite for aluminum also? If you have alot trouble with the threads again I would Heli-Coil them. You can retain the 1/4 size but will have steel inserts in the holes and its MUCH stronger than aluminum that it will be in. The military and aircraft industry them alot and you can do it yourself. Its not cheap though as your buying a tap and drill in the kit.