I wanted to remove the spindle and bearings from the headstock on my
taig mill. I removed the pulley, top nut, and small allen head screw
on back of headstock. But the spindle will not come out.

Any tips or tricks to removing this? I wanted to convert to an ER-16
collet chuck. Just want to see exactly what bearings I'll need if any.
The ER-16 has a 5/8" shank, which is the same size as the upper part of
the taig shaft, but since I can't remove it, I'm not sure what the rest
of the shaft is. I don't think the shaft can slide through the
bearings since it has threads at the top. So I'm not quite sure what
to do next.

Thanks.