I want to take the knob off the handle of my John Deere walk behind so that I can put a wingnut on it instead of the knob, so I can readily fold the handle down to put it in my truck. There is a metal piece on the outside of the hand that threads into the know, but it will not unthread. I have tried used pliers on the knob while trying to unthread the metal but it will not come off - any ideas? Thanks