I'm having a hard time getting the coarse focuser knob off of an A-T/APM/LUNT/TS etc. 3.7" focuser to install an autofocuser stepper motor. Has anybody managed to do this with the 3.7" focusers yet? As in the photo, the bottom knob is the coarse focus, I removed the outer grub screw used as a cover then removed the two grub screws on the black knob inside the focuser body that seem to hold the knob on but the knob itself refuses to come off. I don't see anything else holding the big black knob on, am I missing something?
Thanks in advance!