Unscrew the bottom retaining collar then loosen the 3 retaining screws then unscrew the knob.
Thank you.
Once the locking collar was loosened the knob just unscrewed.
Now I can try to make a knob out of Holly wood. It should finish much like ivory and it is hard. I have a coffee tamper with holly wood and it is very solid.
If it turns out to be a failure then that nice aluminum one from Morgan is in the bucket list.