If you dont have the gear to machine it yourself (I would try and have it done as I am also a cheapskate) I would imagine somone who machines automotive flywheels may be able to do it, there is a fair bit of metal in there and its not like they are pushing a lot of force through them as they only move the mower around, dont get me wrong if it was part of the cutting system scratched up I would probably try my hardest to find a new one.
