Need help diagnosing lower than expected efficiency

[gifty74]

Thanks for describing it. I get what you are saying, and I adjust the roller end to end the same, with a feeler, just like in that video. The issue with my mill is the top two rollers are fixed, just like the Monster mill. When the eccentric cam adjusts it close to the one top roller (like in his video), it pulls it away from the other top roller. So, you end up with a different gap between the dummy roller, and either of the top two rollers. There's only one setting, given how an ellipse works, where the gap is the same out both sides. On my mill, the grain can go out either side. Both top rollers are driven together, and depending on which piece of grain catches the bottom roller, i'll start spinning that direction, and it randomly will go out either side. Which side it comes out is not controllable. The guy in that video says 'if the mill is working properly, it'll grab the grain and come out that side you adjust'. Mine can go out either side, and the gaps are different. End to end across the roller the tap is the same, I have that down.

Here's a video of mine showing exactly the issue:

 

[Brockness Monster]

Welp, looks like there is an issue with 3 roll mills that have the top 2 rollers geared. Not sure how to help you on this one

 

[gifty74]

Welp, looks like there is an issue with 3 roll mills that have the top 2 rollers geared. Not sure how to help you on this one

What mill do you have? Have you taken both sides off and verified what the gap is on both sides?

Geared or not, if the top two are fixed and the bottom is adjustable, don't see how it's possible to not have a discrepancy. Even the non-geared monster mill is the same way as mine in the video. And you'll note he says 'if the mill is working properly...'. How do you know if it's working properly? The path of least resistance wouldn't somehow apply to these mills, and the grains would always go out the side you adjust, even if it is a much tighter gap than the other side?

 

[Brockness Monster]

I have an MM3 that is not geared, no issues with efficiency (84%+)

Edit: I have been wanting the geared M3, but now I think I'll pass

 

[gifty74]

Have you taken the sides off while it is operating to confirm grain is always coming out the adjusted side? If not, how do you know?

The issue with non geared ones is that the grain will get caught up in the top two rollers because only one is driven. You don't ever have issues with grain not feeding? Never have to stop and restart it?

 

[Brockness Monster]

Starting and stopping is a separate issue that I believe to be a design flaw in the hopper. Others have made modifications to their hopper that significantly reduces feeding problems. In fact, something that I need to test soon, I have heard/read that putting a gallon water jug upside down with the bottom cut out in the existing hopper and putting the grain in the jug will allow even feeding into the rollers.

On the subject of whether my grain goes through the proper side or not, I don't have issues with efficiency, so I don't feel a need to check. My rollers are set at 0.025" on one side which would open the other side up quite a bit. 0.050" if I am not mistaken. I am not sure that the bottom roller can rotate the wrong way in a system where only one top roller is driven. I think the reason you are seeing this happen is that with the gearing, both of the top rollers are effectively driven so the bottom roller can roll either direction.

Note the absence of definitive wording here. I am sure someone else can verify the validity or naivety of these statements.

 

[gifty74]

Like you say, your consistent efficiency says that it should be going out the .025" adjusted side every time. And i agree, with only one driven, it should be going out that one adjusted side every time. But, it seems even if top dummy roller isn't driven, if the grain goes in that gap, it's going to run and in essence be driven by the grains going through. It has to rotate in that driven direction, like it would in mine with the gears driving. And if it's rotating that way, with inertia, I would think it would have the ability to grab grain and start the bottom dummy roller rotating in that direction and putting it out the non adjusted side. That's where my issues popped up, and made me dig into it. It's when I went from .030" down to .025", it pumped it out the non adjusted side and after getting lower pre-boil OG than expected, I went and looked at hte spent grain and saw a lot uncracked. It was obvious it wasn't being milled at .025", so dug into it and found the issue. If I get the bottom roller rotating, or just watch and make sure it heads out that direction, I'm good. Once it starts rotating that direction all grain goes that way. As long as the hopper stays full it's all good. Its just I didn't know that was happening. The other solution would be to connect the non adjusted side roller with the bottom dummy roller, which would make sure it's always rotating in that adjusted direction. I tried a rubber band but it broke within a few turns.

And yeah, not sure I want to go back to the issues I had with a non driven idle roller. It was only a 2 roller, but has the same issues of grain not feeding and it stops and even though the one roller is driving, it won't feed.

Ultimate seems to be a two roller with gears or a belt that has an adjustable range and still allows for the gears to work, even if maybe a little more backlash. A belt that stretches a little could be a nice design as well.

 

[Brockness Monster]

yeah, a belt from one of the top rollers to the bottom would help. I wonder, if you wedge a piece of wood into the desired gap between top and bottom rollers, it should prevent it from starting to roll the wrong way and fall out when it starts to roll the correct way. Also, it would also be easy to retrieve from the mash tun as the wood should float to the top of the mash.

 

[BeerNsteadofH2O]

Thanks for describing it. I get what you are saying, and I adjust the roller end to end the same, with a feeler, just like in that video. The issue with my mill is the top two rollers are fixed, just like the Monster mill. When the eccentric cam adjusts it close to the one top roller (like in his video), it pulls it away from the other top roller. So, you end up with a different gap between the dummy roller, and either of the top two rollers. There's only one setting, given how an ellipse works, where the gap is the same out both sides. On my mill, the grain can go out either side. Both top rollers are driven together, and depending on which piece of grain catches the bottom roller, i'll start spinning that direction, and it randomly will go out either side. Which side it comes out is not controllable. The guy in that video says 'if

I have an MM3 that is not geared, no issues with efficiency (84%+)

Edit: I have been wanting the geared M3, but now I think I'll pass

The geard mill is excellentl, it's far superior to the non geared version- but to each their own, I mill barley @ .040 and wheat and rye at .035- never an issue.

 

[gifty74]

Thanks for your input. .040" on the dial on the mill, or with actual feeler gauges? At .035" I get a lot of un-cracked grains.

 

[BeerNsteadofH2O]

Thanks for your input. .040" on the dial on the mill, or with actual feeler gauges? At .035" I get a lot of un-cracked grains.

Feeler gaugers, I measured. 045,..040,.037,.035,.032 and marked each setting so I don't have to remove the hopper each time I change a setting .

 

[ITV]

Just to update here, I found the cause of my efficiency inconsistency. In a nutshell it was my 3 roller grain mill, and the inherent design issues that come along with this, and most style, 3 roller adjustable mills.

I was digging into every possible cause, and finally decided to disassemble the grain mill down far enough that I could really see what was going on, and how the adjustment was actual versus what it was showing on the adjustment dials. The adjustment is made possible by the bottom roller (dummy, non driven roller) that has elliptical ends that sit in a pocket, and as you turn the knob, the ellipse turns in this pocket and moves the roller closer or further away. The issue is that depending on if you are adjusted tight (say .025" gap with the one top roller), the dummy or lower roller is then further away from the other top roller. So a .025" gap will be .035" or .038" gap with the other roller. So, as I was tightening it on the one side, the side that the adjustment is for, it actually opens up the other side wider. And, when you start the mill (mine is powered by a low RPM electric motor) the grain can go through either side, or can be crushed by either one of the top two rollers and the bottom roller. And its random, sometimes it'll go through the one side, and sometimes through the other. So, you never really know what you're getting, truly. There is an adjustment point, around .032", where both rollers are the same distance from the dummy roller (based on it's elliptical travel). So I've set it there, and for any other width gap, I'm going to have to watch and make sure the grain comes out that side roller so I know it's being crushed to that amount that I've set (with feeler gauges).

In a nutshell, it seems most all 3 roller mills have this same design flaw, and I'm not quite sure most know of this issue. It was one of the last things I looked at, but now I know after digging into it and how it functions.

Hope this helps others.

I took measurements on my non-geared 3 roller mill and verified what you stated.
My mill has smoked acrylic panels on the side so I can see which direction the third roller is spinning and it never has spun backwards.

Regarding the non-geared 3 roller mills getting "stuck", I have found that taking apart my mill to cleanout the bushings and re-oiling them (usually every 3 uses) has drastically reduced the frequency of getting stuck. I can also tell by spining the non-driven rollers by hand if it needs a good cleaning by how easily it spins.

With your geared mill, I question what caused the third roller from spinning backwards?

 

[ITV]

With your geared mill, I question what caused the third roller from spinning backwards?

It dawned on me that the reason my mill never spins backwards is because I always pre-load it by manually turning the shaft and the third roller to allow the grain to engage all three rollers so that when I apply power I don't get a free-wheeling roller.

Maybe you can try the same for your third roller?