Quote Originally Posted by Chas Ixion View Post
No idea about the end of the stepper,

Judging by the state of the table corrosion is highly likely. I'll try and get some penetrating fluid in there to do it's work before getting the hammer out.
Penetrating fluid is more likely to do more harm than good near a spindle, and will make no difference to any corrosion that may be on the spindle taper. Just get somebody to swing on the release lever while somebody else taps the holder with the hammer.