Mike, the front is smaller than the rears, if I use my drill bit holder as a guide/measurement, the front gear wire is about .0125 to .0135, and the mains are from .025 brass wire. Mine is leftovers from some resin ship kits, but K&S sells brass wire at most local hobby shops - especially those that sell radio control airplane kits. I think even Hobby Lobby has K&S metal products.

Kevin