Motorizing Your Grain Mill

How to turn your hand powered grain mill into a motorized one.

If you are like me, and most others I know who crush their own grain, you set up is pretty simple, a mill, and either you are hand cranking it, which sounds terrible, or you hooking your drill to it, and powering it that way. I personally am the latter, I hook my battery powered DeWalt drill to the mill and try to hold the speed slow and steady. This is a PITA for two reasons. First, I can never hold the speed the same for the entire crush, especially if its a rather large grain bill, and, this may not be true, but I feel like it cannot be great for my drill to run it with the trigger barely pressed for 15 minutes. And second, I cannot multitask when im grinding. I have to just sit there and hold the drill with one hand and add additional grains to the hopper with the other. I feel like its just a huge waste of time. I have seen setups where people mount a drill and set the speed buy using a zip tie to get the trigger just right. This wasn’t going to work for me because I don’t have a spare drill laying around I can donate to something like this, as it would have no other use. And if I’m going to buy a drill for this purpose, then I might as well just buy a motor to power this thing. And thats what I did.

Parts list

  1. Grain Mill
  2. Motor (12V, 160RPM)
  3. Coupler
  4. Power Supply

During my experimentation of this project I went through 3 different power supply units before settling on this one. I mean it needed to be 12v DC so that part was obvious, but I started with a 7A, the motor wouldn’t even turn on, then went to a 10A. This one worked, however, if it got even slightly jambed up, it would stop, and I would have to clear out the entire hopper to get it going again. It was terrible, especially as I wanted to do this build so I could fill the hopper and let it grind and go do other things, not babysit the grinder. After upgrading to the 20A its a beast and it has not jambed up on me not once.

Wire it up

This build is extremely easy, you run in the AC wire to the +/- and ground. Then the motor has red and black wires, its DC, so red goes to V+ and black goes goes to V-. Now, if you read any of my other blergs, I had an extra AC Rocker switch laying around from my BrewPiLess build, so I added that to my build to make it easy to turn the grinder on and off (you can find a wiring diagram on that post, just put it on the AC input in front of the PSU).


Thats pretty much it, I have this mounted up in my brew table, as you can see in the video, I secured it down with a U-bolt. Let me know if you have any questions, but this is a pretty straight forward build out, and saves me a lot of time, and I didn’t have to sacrifice a drill.

Thats it! Pour one for me, cheers!

Tags: homebrewing  diy 
Written on August 21, 2019