Some others use the a drilling machine attached to the mill axis. Works fine but over time eventually damage your drilling machine.
I found a old motor, saved from a old washing machine with 1/2 Hp and running in 127Vac.
This is a standard grain mill, with the handle removed, and attached a pulley with 150mm diameter.
With an old wooden stand for CPU, I decided to adapt and fix the mill, including a new wooden support.
For this I cut and pasted a new piece of wood, trying to leave with a nice appearance.
The quality was not very good in appearance, but is very functional and fixed.
The next step was buy a "VA" belt in necessary length and mount the motor using a metal plate to fix the motor in the wood.
The relation between pulleys wasn't calculated, but I imagine around 120 rpm in the mill axis.
The belt is loose, if a crash occurs, it simply escapes, preventing motor burn.