[emeritus]

I have repaired broken plastic knobs where the plastic socket that engages the shaft has disintegrated, by gluing the broken bits together, winding plenty of turns of thin steel wire firmly around the plastic socket, and then encasing the wire in Araldite. I use stainless steel dental wire that I picked up many years ago in "Proops" emporium that used to be in London's Tottenham Court Road, but I have seen similar wire sold as binding wire in Yacht chandlers.