[skyler]

I figured I would give an update since I believe I bought one of very few 2-roller geared mills on the market (Crankandstein 2DG) and I just had the chance to test it, giving it a good "cleaning" by milling some very old malt destined for the compost. It does mill with my decent-quality DeWalt corded 3/8 inch drill, which is a requirement of mine. However, I will note that it is extremely loud (and annoying-sounding) compared to a non-geared 2-roller. I have a garage and a backyard, so that isn't a dealbreaker for me, but it is worth knowing about. Also, it takes a lot more torque to get this to grind compared to the old non-geared 2-roller mill. As a bonus, it fit perfectly in the hopper and base that I got with my old Crankandstein 2DT 14 years ago, which made my life a bit easier. I still wish the housing covered the sides of the mill, and I would prefer if it was somehow less noisy, but it works as promised. I'm planning to brew two beers (and mill 32 lbs of malt) this weekend, so I will get the opportunity to see how it performs with lots of conditioned malt soon enough.

[CounterPressure]

Is it the gears that are making all the noise? That kind of makes sense. If I was to do gears on mine I would make them out of Delrin so as to be essentially silent. And of course I have it at work so I don't need to go buying it. Making steel gears wouldn't be my first choice, in spite of the fact that I have numerous gear Cutters and a four-axis Machining center.

One thing I would caution you on when you make the statement about the horsepower requirements as well as simply the terminology there. And I don't mean to be pedantic here, but the idea is absolutely not to grind the malt. The idea is to crush the malt. There is a very big difference. You're not trying to make flour, that's what a Corona Mill does. The Malt we use is plenty frangible already, and it produces more dust than we want even when we crush it properly. The problem is, most mills do not crush, they grind. Doing exactly what you said, except the one you just bought does not. It does a proper Crush and I think you're going to see a very big difference in your lautering. Because of the size of my rollers in my Mill it is very close to producing an ideal Crush. But I have videoed the thing with tape on the shafts and I can say that there is a small amount of slippage on the second roller which indicates there is some grinding taking place. I know the amount isn't much, but it's non-zero. I think non-zero is what big commercial breweries are aiming for because that gives the best performance both in the mash efficiency and lautering ( meaning no stuck sparge).

From what I understand, smooth rollers are the ideal situation but they've got to be 6 in diameter or greater. Otherwise the malt will not pass through because there's no traction on those things. I think if I was ever to make a mill with rollers that size I would still put the very fine knurling that I have on mine, on to them because it just doesn't make any sense not to. 5 minutes and you've solved a lifetime's worth of headaches. I can't believe nobody else uses that straight knurl.

[skyler]

My statement about the torque requirement had more to do with people who might expect to use a battery powered drill or hand crank — my battery-powered drill couldn’t handle it and I don’t think Most brewers could handle milling more than. A pound of grain with a hand crank using this thing. It feels much much harder than turning my identical (besides the gears and wear) mill.

[CounterPressure]

Grinding doesn't require a lot of power.  Crushing, takes a lot of power.  But one method produces a maximum of dust while the other produces a minimum.  Not zero, but way, way less.  Extract efficiency is not significantly reduced either.  But the sparge goes way easier and faster.  You'll see this weekend.  I wouldn't be surprised if your new mill pays for itself in increased efficiency.  You can actually crush more, while not getting a stuck sparge, and efficiency will increase.  But does so without tearing up husks and causing other flavor issues. 

[larry4406]

@counterpressure do you have links to pictures of your roller mill that you built?

[CounterPressure]

@counterpressure do you have links to pictures of your roller mill that you built?

Other than the ones I already posted in the thread? No.

[larry4406]

@counterpressure do you have links to pictures of your roller mill that you built?

Other than the ones I already posted in the thread? No.

The pictures in Reply 8 don't show up for me.

[CounterPressure]

The pictures in Reply 8 don't show up for me.

Right click and open in a new tab. I don't pay for a security certificate for my hosting so I or anyone else who posts a photo hosted on such a server will get the placeholders like that but not the images because of course they're trying to keep you safe from all the horrors of a JPEG image

[larry4406]

The pictures in Reply 8 don't show up for me.

Right click and open in a new tab. I don't pay for a security certificate for my hosting so I or anyone else who posts a photo hosted on such a server will get the placeholders like that but not the images because of course they're trying to keep you safe from all the horrors of a JPEG image

This worked, thank you.

[CounterPressure]

... However, I will note that it is extremely loud (and annoying-sounding) compared to a non-geared 2-roller. I have a garage and a backyard, so that isn't a dealbreaker for me, but it is worth knowing about. ...

I gave this some thought yesterday as I was researching making gears for my mill. (actually, will be a whole new mill, but, gears all the same).  I thought I had a gear cutter here that would work, but as it turns out it will not. It's actually for much smaller gears than I want.  Correct gear pitch, just not the correct cutter for that gear size and tooth count.  It got me to thinking about your statement about how loud that thing is.  It's possible they cut those gears with the wrong cutter.  Or maybe didn't even use a gear cutter, Idk.  Bottom line though, I have made gears with the incorrect cutter before and experienced what you describe.  In my case, I was using a plastic gear in tandem with a steel gear, so that the plastic gear was mis-cut didn't really matter since it would eventually wear to fit, so to speak.  It was the second replacement of it in 25 years, so I wasn't worried about it failing due to the wrong cutter (and not buying the right one just to make it sound nicer).


There's some math involved in determining the correct gear cutter. It's not rocket science, but it is important.  Any gear (involute gears) will require one of 8 cutters depending on what size, shape and tooth count they have.  The cutters are numbered 1-8, with 1 for the smallest gear of that pitch and 8 being the largest, or for making a straight gear rack.  Using the wrong one for the diameter will result it a gear that makes a lot of noise, at least for a while.  In steel, likely it'll make noise forever.

Yesterday I bought a set of 16 diametral pitch gear cutters so I'd have the correct one to make a 46 tooth gear, which is what I need to make my 2.880" pitch diameter gears. (my rollers are just under 3" dia so I need the pitch diameter of the gears to roughly match that in order to have them work with those rollers. )


I found these gears on ebay, but they are 1 tooth too few for my roller diameter.  Story of my life.
https://www.ebay.com/itm/35336955 3481

[Drewch]

There's some math involved in determining the correct gear cutter. It's not rocket science, but it is important.  Any gear (involute gears) will require one of 8 cutters depending on what size, shape and tooth count they have.  The cutters are numbered 1-8, with 1 for the smallest gear of that pitch and 8 being the largest, or for making a straight gear rack.  Using the wrong one for the diameter will result it a gear that makes a lot of noise, at least for a while.  In steel, likely it'll make noise forever.

I remember covering gears in my undergrad machine design courses. It still blows my mind that people figured all this stuff out on paper by hand .... some of these design standards even predate slide rules.

[CounterPressure]

I remember covering gears in my undergrad machine design courses. It still blows my mind that people figured all this stuff out on paper by hand .... some of these design standards even predate slide rules.

The geometry involved is otherworldly.


If you'd like to have your mind blown watching a gear making process, check this out. Yes it's long, it is well worth it.
https://www.youtube.com/watch?v=m-kFF76bNqw

[brewthru]

I remember covering gears in my undergrad machine design courses. It still blows my mind that people figured all this stuff out on paper by hand .... some of these design standards even predate slide rules.

The geometry involved is otherworldly.


If you'd like to have your mind blown watching a gear making process, check this out. Yes it's long, it is well worth it.
https://www.youtube.com/watch?v=m-kFF76bNqw

Makes me think of those very smart individuals whom designed/built bridges, etc in the late 1890s/early 1900s. Amazing people.