A quick and easy method that I've used with success is to fill the stripped hole with slivers of wood and a little wood glue (waterproof in this case) and then just replace the screw. Make sure to trim the slivers flush and if the screw doesn't grip add more slivers. Waxing the screw is probably also a good idea in the method. Rick Langer M15 #337 Bluebird