[captainclock1988]

If you can figure out how to put the pieces back together for long enough to make a mold, then you could cast the part. The mold putty is pretty easy to work with. Then use a 2-part plastic mix. It does not look much more complicated than a knob. Lots of people make knobs for themselves.

I did try to glue it back together, but then it broke apart in other spots, unfortunately the bakelite, (or whatever kind of plastic it is) is too brittle to try and make a mold out of it.