Although I do knot usually recommend whacking the Mark V with a hammer, but if it truly is only rust preventing the quill from moving
, one thing that you could try is this: Put something, like an empty saw blade arbor, on the shaft, to protect the end of the shaft, and give the end of the shaft a good whack. This might
break loose the rust. This method has helped me with similar (non-ShopSmith) situations. Hopefully someone else has a better idea! Good luck.