Adjustable RPM screwdriver to use with manual grinders?

Recommendations for buyers and upgraders from the site's members.

#1: Post by boren »

I have a 10.8V screwdriver that's powerful enough to work with my manual grinders (1ZPresso K-Plus and Kingrinder K0, K2 and K6). It even works well with light roasted beans, but unfortunately it goes to maximum speed 550 RPM (no load) which is too much for my liking. In theory I can use slower speed by pressing the trigger more lightly, but it's difficult to do so consistently.

I also have a 3.6V screwdriver which maxes out at a more sensible 200 RPM (no load), but it's not powerful enough. It only works without stalling with the Kingrinder K0.

Are there electric screwdrivers that are powerful enough and that allow limiting maximum RPM (or better yet - controlling it accurately)? Would an 8V screwdriver that maxes out at 230 RPM (like this one) be the ticket for motorized "manual" grinding?