Grain mill design questions

Hey all!

I am making my own grain mill. I have a few options in the design, having to decide quick, so please give me your opinions!

Here is what is set:

Motorized at 15 inches / sec (is what I have found is ideal speed)
Roller(s) diameter of 1.5 inches, aluminum (no steel due to machining capabilities)
Roller or Plate adjustable

What I am trying to figure out is;

Do I do one roller and an adjustable plate?
If so, smooth roller and smooth plate (crush, no hull shredding, potential feed issues) or knurled roller and smooth plate (no feed issues, potential hull shredding)?

Do I do 2 rollers?
If so, smooth rollers (crush, no hull shredding, feed issues?), 1 knurled (fixes feed issues, potential hull shredding), or both knurled (great feed, highest potential for hull shredding)?

So I have a lot of potential combinations. What would be best?

sP / sR
sP / kR
sR / sR
sR / kR
kR / kR


I am leading towards sR / kR so I can have one to feed the grain without as much shredding of hulls. I would go with sR/ sR so I am not shredding the hulls at all, but I am concerned at only 1.5" diameter on both rollers I am going to have grain feed issues.

Thanks for feedback and any ideas!

My brother in law has machined a small mill for me. It has two rollers one slightly larger, each with a slight knurl. Total roller width 4 inches. Four small bearings and one of the rollers has a concentric design to allow for adjustment of the gap. Off to one side will be a groove for a O ring to ensure the rollers spin before the grain starts pouring in via an automotive funnel.

i think if you drive one roller, you should eliminate most of the shredding - as long as the other roller turns freely with the grain. I haven't seen the plate type but i know my adjustable 2 roller (both knurled) works really well. Its driven by one roller. never noticed any issues with shredding.

good luck and post lots of pics!!!

Just curioius - do you have materials available at a cheap price? i think you couldnt build a mill as cheap as you can find some when they are on sale. Unless you are doing a bigger custom build.

kegtoe said:

i think if you drive one roller, you should eliminate most of the shredding - as long as the other roller turns freely with the grain. I haven't seen the plate type but i know my adjustable 2 roller (both knurled) works really well. Its driven by one roller. never noticed any issues with shredding.

good luck and post lots of pics!!!

Just curioius - do you have materials available at a cheap price? i think you couldnt build a mill as cheap as you can find some when they are on sale. Unless you are doing a bigger custom build.

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I will post pics as I build and get it completed for sure!

As for materials; the aluminum I have for the rollers is scrap I got, and I have a coworker that has a machine shop at home who is doing the work on those for me. I found a good surplus motor, and through that and McMaster-Carr for parts I am looking at about $100-$120 for the mill when all is said and done, with a motor run roller and a free rolling roller or plate being fully adjustable. I might, might find something cheaper, but as an engineer and tinkerer I find a lot of joy in making my own things! DIY baby!