>1) Lower the quill.
>2) Look for a hole in the back of the quill.
>3) rotate the spindle so an Allen socket lines up
> with the hole.
>4) Reach in through the hole, loosen the Allen socket a partial
> turn, and reach through that socket to another behind it.
>5) Unscrew both fully, and draw out (trying to not lose them
> inside the quill.
>6) Replace the front one (a dog point Allen head setscrew where
> the dog point acts as the pin in the spindle. When it is set
> deep enough (check that it does not bind on the collet with the
> shallowest key groove), withdraw the Allen key slightly so it
> only engages the outer Allen head screw -- which is *only*
> socket and threads, no body beyond the socket) so it locks
> the dog point one in place.
> Now -- I've only read about this, never done it, so I'm trying
>to remember whether you have to turn out the big nut at the bottom of
>the quill first. If so -- mark it so you can screw it back in the same
>amount. It has its own set screw holding it in place.