As Em`s get older, this is something that there might a market for, I thought I had a bunch of G10 around but I think they got tossed.

I would try to drill the center of the nub with a 1/32nd bit, after filing it flat first, (leave as much material as you can tho), find a small piece of G10 fiberglass or similar, drill the same thru the piece, insert a piece of wire (paperclip) thru the new piece and into the wheel, using epoxy or your glue of choice, then shape to contour of original

Have never done this, but it is what I would try first

Good luck