I have a mill (Barley Crusher) that I motorized after using it by hand exactly once.
First with a 1/2" drill - much faster but the speed was inconsistent. This may have made the crush uneven but I can't really say for sure.
Then I built a collapsible table with a 1/2hp motor. Worked great and fit perfectly with my "I'm really kind of lazy" attitude. No cranking, no holding the drill and it stored easily by hanging it on the wall.
Lastly I built a small table with wheels that I can roll around. I also found a newer, nicer motor so a rebuild was going to happen either way. Now it fits perfectly in my "I'm really kind of lazy" attitude because all I need to do is pull the table forward from the wall, plug in the cord, flip on the switch and pour the grains in the hopper. Then i can busy myself with other tasks until it is done milling my batch.
Besides supporting my laziness, this setup also gives very consistent crushes and is ready at a moments notice with no setup or heavy lifting. It also cleans up easily with a shop vac.
I been known to work very hard to eliminate work in my brewery.
*** Edited to fix a spelling error.