Adjustable Mill Rollers?

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NoShopSkills

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Hi;

I have time and scraps to build a knurled roller grain mill, for crushing barley for my favorite hobby, home brewing of beer. There are some very good stainless roller models, that use 6061 aluminum plate for the ends. Thay retail for around $150-200, (for instance the Monster Mill MM-2), but I want to build my own with slightly longer rollers that I may power with a 1 HP 120v electric motor, a 1/2" power drill or even a hand crank. Problem is that I have no understanding of how the "on the fly" gap adjustment works.

Most of the commercially available models have 2 rollers. One is driven and the other freewheels. The knurled surfaces of the rollers insure that the grain is grabbed by the driven roller and pinched as it is crushed, thereby driving the free wheeling roller. More advanced versions for larger operations, like micro breweries, use gears to drive all rollers and some even have 3 roller set ups. I'm fine with a 2 roller system as I'll likely only grind 20 pounds or so of grain at any given time and since it's a hobby a few more moments crushing grains once a month is no big deal even if I have to run the grist twice to get the proper crush.

The interplay between the rollers has to be adjustable. Different types and differing moisture content of various grains need differing amounts of pressure (distance between rollers) as there is no 100% universal gap that always works best for each grain type.

I own a stainless counter mounted pasta noodle roller that works on the same principle I'd like to build. One rotary knob changes the interplay at both ends of the roller, keeping the axels of the rollers perfectly parallel. It's ends however are stamped stainless steel sheet metal. If I take it apart and for some reason can't get it back together correctly, just to see how the adjustment knob changes the spacing, I'll be upset.

I could machine a bearing slot in the end plates and use some sort of jack screw set up to change the interplay, or a dual cam device (one on each end plate) that has an exterior tie bar but the one knob adjuster in the pasta roller and the Monster Mill is so slick. Can anyone begin to help me understand how it works? Maybe a sketch of the mechanism?
 
I haven't brewed in about 10 years, I finally had to quite when I realized I had gained about 30lbs because I had home brew available on tap all the time!

The adjustable rollers are typically made so that the non-driven roller is free spinning on a shaft that is more or less like a crankshaft. The non-driven roller is free to rotate around the part of the crankshaft that would normally carry the connecting rod. The main center of the crankshaft is connected to an adjustment knob or lever that can lock in different positions allowing the non-driven roller to be positioned different distances from the driven roller. It's really rather a simple mechanism and is used on other machines like back gears for lathes. I would not take your pasta machine apart! I know this isn't a great explanation but I will continue looking for a diagram that may help. I believe the proper name for this mechanism is eccentric, but typically the shaft is rotated in operation (like when driving valves for a steam engine) but in this case the shaft is locked and the non-driven roller is free to turn around the eccentric. I'm hoping someone with more of a mechanical engineering background can explain this better.

You may find that a jack screw setup works fine. I typically didn't mess with the adjustment on mine once I had a crush that worked well. Since you are not doing production brewing getting the last little bit of fermentables out of the grain isn't that big of a deal. Also you will probably find that a certain level of crush works best for your mash tun.
 
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Yeah I figured some sort of eccentric was the key. Thanks. I think I can visualize solutions using that idea, but getting it right might take far more time than I had thought this project might take on the front end.

Meanwhile I think I came up with another idea that may work: Rather than one piece axel mount plates, two separate end plate carriers that are hinged together an inch or so off center. That way changing the hinge angle would change the distance between the axels. Maintaining the desired relationship could rely on an all thread rod, or a locking cam device.

did you ever loose that 30 pounds?
 
Think of a slop roll sheet metal roller, move the roller bearings with a driven lead screw on each side, this is 18th century technology.
 
I completed knurling the schedule 80 - 2" pipe this morning, but had to stop, to take the dog out on the boat and patrol for bikinis. I like the jack screw/driven screw idea. I'll try to post some pics after the 4th (of the machining work not the bikinis...different forum)
 
NoShopSkills said:
I completed knurling the schedule 80 - 2" pipe this morning, but had to stop, to take the dog out on the boat and patrol for bikinis. I like the jack screw/driven screw idea. I'll try to post some pics after the 4th (of the machining work not the bikinis...different forum)
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Which Forum would the bikinis be on?
John, trainee Dirty Old Man since 1967.
 
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