I purchased the 3/16 inch wire from Robart. You can go to their web site and look for the top-flite AT-6 gear. It will show the gear with the wire in it. They sell the wire for $12.00. Just drill the existing gear hole out to 3/16 inch and push the new wire in. Be sure to file a flat spot where the allen screw sets against the wire so it will not twist. As far as building tips go, I did everything according to the manuel except I left the wing strakes off. I just didn't like how they fit and they looked cheap. I used thirty minute epoxy to strengthen the inside firewall and that is about it. Take your time on the cowl. I spent quite a bit of time to get the dummy engine to fit right. I also installed a tru-turn AT-6 spinner. Good luck and happy flying!