On Sunday, May 3, 2015 at 9:18:53 AM UTC-7, John Doe wrote:
[about coupling to a drill motor's output shaft]

The spindle attachment was nearly what I was looking for. Just something
to keep from destroying the spindle and therefore rendering the cordless
drill useless.

Hie thee to a thrift store and get an orphan cordless. Drills, screwdrivers,
saws, even lawnmowers... there's LOTS of motor/gearbox options, as long
as you don't plan to put it back together and plug into a working original-manufacture
battery.

Be aware, though, that anything with inertia will unscrew itself from a threaded
shaft whenever your motor stops.