DIY grain mill

Ok, my next project is making a grain mill completely from scratch. I'm going to basically copy this dude's design, but I have a few questions for anyone who cares to read further.

I'm planning on 2 inch rollers, just like the link above - does anyone have a a suggestion/reason for a using a different diameter?

The link shows mild steel rollers - I'm a bit concerned with rust if I machine mild steel that clean, and I don't want to lubricate the rollers with any sort of food grade rust inhibitor (mineral oil), as that will cause clumping. Stainless is too expensive. I have access to both aluminum and steel round bar. Seems to me that aluminum would be easier to operate (lighter...less inertia), and as long as I'm not grinding flour, it won't dull/wear very readily. Opinions?

I have the option of powder coating the rollers. I could use a thin gloss coat or matte finish, or I could use a textured finish. This would prevent the rust problem in mild steel, but might it adversely affect performance?

Lastly, what RPM do you think I should use? I'm thinking between 100 and 300 will suffice (52 to 157 SFM - surface ft/min), but I've seen some that operate a bit faster.

Let me know what you think - anyone's opinion is appreciated!

While aluminum has better corrosion properties, I think I'd still try to go with steel for two reasons, the primary one being inertia. A bit of flywheel weight will help you get a nice and smooth running mill. Of course you could add a flywheel to lighter rollers, but that adds a bit of complication, (though not that much.) Of lesser importance would be the hardness of the rollers, grain might not be that hard, but it is abrasive like wood is and aluminum would wear more quickly than would steel.
Two inch rollers would be nice. They would keep shock loading to a minimum by giving the grain a longer sqeeze, they would require more power, but less torque to operate- another reason to increase your fly-wheel mass.

Cha-ching! $0.02

Keep us updated on your progress/decisions. I was going to build one before I stumbled on a great deal and bought mine.

Chairman Cheyco said:

A bit of flywheel weight will help you get a nice and smooth running mill... ...Of lesser importance would be the hardness of the rollers, grain might not be that hard, but it is abrasive like wood is and aluminum would wear more quickly than would steel.

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The "flywheel effect" was something was wondering about as well - I think you've made up my mind - I'll make steel rollers unless someone else has a VERY convincing argument for aluminum.

Still undecided about the powder coating - anybody?

do you have access to a machine shop?

Todd said:

do you have access to a machine shop?

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Yup! Not quite a full blown shop, but lathe/mill operations of this size are no problem.

I used a aluminum magnetic roller (magnet inside) from primncess auto and a fiber glass fuse used for power lines. (I worked for the power company for a while) Both are 2 inch, I use rubber o-rings around the ends of the smooth fibergalss roller that casue it to spin via friction with the milled alum roler. Works great.

Uhm... when it comes time for me to go to all grain I think I'll just stick to this little number. It'll go nicely with all my other attachements...

omniscientomar said:

Uhm... when it comes time for me to go to all grain I think I'll just stick to this little number. It'll go nicely with all my other attachements...

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Yeah, I saw that little guy. We have the required mixer and really like it, but $150? I just spent two-thirds of that on enough metal to make about five homebuilt versions...and I'm looking forward to the project.

omniscientomar said:

Uhm... when it comes time for me to go to all grain I think I'll just stick to this little number. It'll go nicely with all my other attachements...

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SWEET!! I didn't know they had this attachment. I never looked at the book that came with it...just unpacked the mixer and used it. Hmm...add a little wood to make a bigger hopper and I'll be set. Anyone used one of these that can comment on it's effectiveness?

Jester4176 said:

SWEET!! I didn't know they had this attachment. I never looked at the book that came with it...just unpacked the mixer and used it. Hmm...add a little wood to make a bigger hopper and I'll be set. Anyone used one of these that can comment on it's effectiveness?

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Guys, you can get a Barley crusher for $130.00 delivered to the West Coast. Just an option to consider.

Yuri, looking forward to how your mill performs. Good work.

Would a burr type coffee grinder work. Not fast production but variable grind and cheap. Most of us have more time than money anyway.

krury said:

Would a burr type coffee grinder work. Not fast production but variable grind and cheap. Most of us have more time than money anyway.

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I don't think it would work very well. It would grind them to fine. You want to have the barley hulls intact and not grind them to flour.

krury said:

Would a burr type coffee grinder work. Not fast production but variable grind and cheap. Most of us have more time than money anyway.

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It's possible you could find one that has a coarse enough setting, but even the coarsest coffee grind I've ever seen would be too fine for crushed grain. I'm opting for the completely home-built version - still a few open questions from the first post...anyone?

Progress! Here's a test piece in 1" aluminum. I powder coated it mostly to test my setup and play with some new garage toys.



Since no one has addressed the coating issue, I might make two sets of mild steel grain rollers as a bit of an experiment - one set in bare metal and one powder coated set.

That's a neat project, Yuri_Rage. I think mild steel would be the best of the options you've mentioned. Try to keep it dry, but a little rust isn't going to hurt you.

Is stainless too hard to lathe? I don't know anything about metalworking, but it seems like that would be a good solution. How about nickel plating the rollers?

beer4breakfast said:

Is stainless too hard to lathe? I don't know anything about metalworking, but it seems like that would be a good solution. How about nickel plating the rollers?

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Stainless is a little harder to machine, but that's not why I ruled it out. It's REALLY expensive. Aluminum and mild steel are much more affordable.

Nickel or even chrome plating is certainly an option, but that adds cost as well, and there isn't a plating shop in town. I have access to all of the processes I've mentioned so far.

FYI, tools are chrome plated because chrome is a VERY hard, durable finish. It's usually a two step process where nickel is applied and polished, then chrome is applied over the nickel plate. Triple chrome plating is chrome plate over nickel plate over copper plate, polished at each step along the way.

There are a ton of places in San Antonio that do plating if you want the numbers let me know it might be fairly cheap.

you can also get a crankandstien for 69 bucks

I use a rotary tortilla press. It has 3" diameter slick aluminum rollers, noisy cast aluminum gears. I made a hopper out of wood that restrict flow to about 1/2 to take it ewasy on the castings, and a bucket top base. I drive it with a socket in my drill motor, about 1/2 speed. New, they are $89 on eBay. Or swap meet with a broken crank, $20. It has adjustable rollers too. It works so well, I think I'll spring for some new precision gears, prolly $30. The aluminum rollers won't rust. Rust will ruin beer by the batch.

It feeds better than the press I made from a 1 1/4 knurled weight lifter's bar, too small diameter, even knurled.

brewhead said:

you can also get a crankandstien for 69 bucks

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But then I miss out on the fun of making my own. They look nice for the price for anyone reading this thread who doesn't want to machine their own parts.

EDIT: Just noticed - these are only 1.5 inch diameter by 4 inches long. I'm planning 2 inches in diameter and 12 inches long. (That sounds really bad...)

Yuri_Rage said:

these are only 1.5 inch diameter by 4 inches long. I'm planning 2 inches in diameter and 12 inches long. (That sounds really bad...)

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... especially when taken out of context.

and on here, it's ALWAYS taken out of context.

How about this nice looking Crankandstein complete system for only $139. Seems hard to beat. Take it out of the box, put it on top of your bucket, dump in your grain, attach drill and grind.

beer4breakfast said:

How about this nice looking Crankandstein complete system for only $139. Seems hard to beat. Take it out of the box, put it on top of your bucket, dump in your grain, attach drill and grind.

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Mine'll be twice as big for a quarter the price.

If you ever hear that on a street corner - run far, far away.

Of course you could by one! That's not the point, we could by beer too! Take it out of the box, open the top, put it to your mouth and dump it in your stomach. Where's the fun in that?

Ah, well, you have a point, Mr. Chairman! The answer, I suspect, depends on what you consider fun.

Great analogy, by the way.

Powder coating may not be desirable- isn't the plastic used generally low friction? I think you want friction to grab the grains. I'd like 4" steel, no gears or knurling. Or 3" aluminum- al has more friction. Chain and Sprockets may be cheaper than gears, either could be added later if it don't feed. Hmm, I should try mine with a gear removed, quieter that way.

casebrew said:

Chain and Sprockets may be cheaper than gears, either could be added later if it don't feed. Hmm, I should try mine with a gear removed, quieter that way.

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Chain and sprockets would require extra steps to get the rollers to counter-rotate.

casebrew said:

Powder coating may not be desirable- isn't the plastic used generally low friction? I think you want friction to grab the grains. I'd like 4" steel, no gears or knurling. Or 3" aluminum- al has more friction. Chain and Sprockets may be cheaper than gears, either could be added later if it don't feed. Hmm, I should try mine with a gear removed, quieter that way.

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Powder coating has just as many finishing options as paint, if not more. I can use a flat finish or even a textured finish to increase friction. I don't think I'll have a friction problem, but the plastic used in the powder coating would almost certainly wear at a pretty rapid rate. Just for $hits and giggles, I'm going to make two sets of rollers, one set powder coated, the other set unfinished, and compare the results. I might experiment with an aluminum set as well.

As for the material - I'm going to use 2" mild steel. 4" dia. steel would have a LOT of rotating mass, and I'd like to keep power requirements somewhat in check. Knurling is going to increase the friction coefficient - I'm not sure what advantage a plain, smooth roller would give unless you're trying to grind really fine flour.

Gears/sprockets: NONE. I'm going to power one roller and use the adjustable side as an idler. The moving grain should be enough to get it rolling, and an idle roller greatly simplifies the design.

Yuri_Rage said:

Gears/sprockets: NONE. I'm going to power one roller and use the adjustable side as an idler. The moving grain should be enough to get it rolling, and an idle roller greatly simplifies the design.

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My JSP maltmill has a viton o-ring on one roller which gets squeezed between them and gets both going. I'm sure there isn't much power being transfered but it does seem to give a bit of impetus when you first start to help it along before the grain starts being crushed. I thought it was an elegant solution.

P.S. A friend of mine has lined up a small engine lathe that is going to live in my garage! I'm gonna have soooo many mills!

Chairman Cheyco said:

My JSP maltmill has a viton o-ring on one roller which gets squeezed between them and gets both going. I'm sure there isn't much power being transfered but it does seem to give a bit of impetus when you first start to help it along before the grain starts being crushed. I thought it was an elegant solution.

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Thats how my home mead eone works, except I'm using a plastic rubber "tape" that temporarily performing that function. I'll replace with orings when I get around to rebuilding the casing for thr mill out of aluminum. The proto was out of wood.

Finally, some progress!!!

I started machining parts for the mill today. Here's what it looks like so far. This thing's going to be a monster with 12" rollers!

Sweet! Is that the Binford 5000 Grain Masher?

How much to make one for a fellow home brewer?LOL

Big and beautiful. Get a pair of those together and I bet it'll do a pound of grain every 1.75 revolutions of the rollers. At that rate, it will never wear out.

j/k about the revolutions. I have no idea really, but I bet it'll throw down some milled grain fast!

Man, I wish I had a mini-lathe and the space to set one up. That is too cool! What metal did you end up using? Plain steel?

That's mild steel - used most of a 36" length of 2" dia. hot rolled round bar. The second roller is just about done (takes a while to turn the axle ends down to 1/2").

EdWort said:

Sweet! Is that the Binford 5000 Grain Masher?

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I think you just named it!

G. Cretin said:

How much to make one for a fellow home brewer?LOL

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Dunno if you could pay me enough to make another behemoth like this out of steel - it pretty much maxed out my setup. I could be persuaded to make a set of 8" to 10" rollers out of aluminum (easier to machine) for around $50...or less if you send some of your homebrew my way!

Rollers are about done!

B........ E.............A..........U..........tiful Your Binford 5000 Grain Masher is already the envy of many. Nice work and thanks for the picts of your progress.

Yuri_Rage said:

I think you just named it!

Dunno if you could pay me enough to make another behemoth like this out of steel - it pretty much maxed out my setup. I could be persuaded to make a set of 8" to 10" rollers out of aluminum (easier to machine) for around $50...or less if you send some of your homebrew my way!

Rollers are about done!

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Send me the particulars and it's a deal.

Chairman Cheyco said:

P.S. A friend of mine has lined up a small engine lathe that is going to live in my garage! I'm gonna have soooo many mills!

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Now figure out how to use the lathe as the mill and your in buisness.