You could find brass tube that just fits over the screw threads and then fit it inside the wheel. The wheel hole would need to be enlarged to get a snug fit over the tube. The tube could extend out from the wheel hub just a little on both sides. Now the threads will not wear the plastic wheels. Please get some help on your first flight. It's not a easy as you would think. Too many people try by themselves and crash their plane on the first try and that's the end of it, never to try again and we've lost another one to the hobby. Check for clubs in your area, they would be happy to help.