The main issue with doing this is the potential to damage your grinder. Your arm has a built in torque limiter, has a feedback loop and only operates at a low s

The main issue with doing this is the potential to damage your grinder. Your arm has a built in torque limiter, has a feedback loop and only operates at a low speed. If you want to do this with a drill I would recommend one with a torque limiter and a variable speed so you can use it at a low speed. There are also other niceties that proper electric grinders give you.