....
That leaves no place for his spindle encoder and a rotating air
connection at the top of the spindle.

Sure it does, his encoder will operate just as well on a hollow shaft as
on a solid one...

Not if its plugged into the top of the spindle with an expanding
arbor......

yep, me thinks Iggy be making a mistake to lose his hollow spindle
just for an encoder. There are ways around it.


I see this thread hasn't mentioned spindle speeders. I use a unit that
mounts just like any other tool and the ouput shaft turns 6X the input
with a set of small collets. Scored mine on the bay for $200 and
change.

Karl