The Stovebolt Site Forums The Shop Area The Electrical Bay How do I remove this ?

First, make sure you have the shaft installed completely in the switch. It shouldn't stick out too far.
The switch end of the shaft is made to catch inside the switch. You will have to remove the knob, cut the shaft , and reinstall with set screw. Put the shaft in a vise and see if you can tap the knob off since you have already removed the set screw. Maybe it was glued on too. Or get a replacement knob after you cut it to desired length.
Good luck.