Brian,
Where the heck were you when *I* wanted to ask that question? :c)
It's a slide on, no spline, but really tight, they may have used a light adhesive (like we used to use hair spray on bicycle grips). In any case, try twisting and pulling - but if the thinner bottom part doesn't move, then it'll be safer to also push up on that with an open end wrench or similar that sort of fits the shaft. I don't think it'll tear. Oh, and if you have a compressor with blow gun handy, direct a stream of air and the bottom of the knob - - that's most always a help.
BTW, I was thinking of maybe further modifying mine, maybe use an end mill to make a half inch hole in the side of the knob and mount a 13mm push button in it. Super glue works on rubber almost as well as it does on skin. Just have to find a suitable button.
'Course the button I have does work . . . and I do have a bunch of stuff to do that should have priority over that, but you know how that goes.
bumper
