Another alternative, that was suggested to me by a carpener friend, would be
to invert the drill head on the column of a table top drill press, so that
the quill points up. Then you bolt the base to the ceiling, so that the
column is a few inches off a nice big flat table top. Viola, a drill press
with no clearance problem between the chuck and the column. Sort of like the
pair of bridge piers I saw once, from which the bridge had been removed; some
wag had posted a sign reading "Clearance- 180,000 miles"