Monster Mill 3 troubleshooting

[SEndorf]

I replaced my crapped out mill with this one.
Seems to be a finnicky setup. I'm using a gear motor with pulleys in parity. 164RPM and 60 in-lb.
At first the mill just locked up, but didn't stall the motor.
Then I played with the gap a bit. Have it set at 48. Now the mill spins but doesn't feed the grain through.
Anyone work with this mill and have any ideas?

 

[RPh_Guy]

Did you use a feeler gauge to make your own gap settings marks?

Do the rollers spin freely?

I'm not sure what you mean by locked up without stalling the motor. I use a drill with mine.

I solved issues I was having with the drill stalling by limiting the flow of grain going through the rollers.

I condition my grain and generally mill between 0.030-0.040". I'm not sure about my rpm, it's the low speed of my drill.

 

[SEndorf]

Yes. Feeler gauge set at .048 per instructional video from monster mill.
Rollers spin freely.
The belt is set exactly to specification. 37" belt / 16 2/16" inches center to center from each shaft. I had to temporarily loosen the motor mount bolts a bit to get the belt on the sheaves.
Both sheaves (mill and motor) are 1 1/2" so their in parity.
I'm frustrated that the grain just sits in the hopper. If I had incorrect gap, I'd assume the top rollers fixed at 0.60 would still pull grain.
At a total loss here.

 

[RPh_Guy]

Sorry, have to ask:
The roller is turning the right way?

 

[kh54s10]

Just thinking... Rollers spinning in the right direction?

 

[Tobor_8thMan]

Was the gap set on the proper side based on how the driven roller was turning?

 

[grampamark]

I used an MM3 for years at the LHBS before I bought my own mill. I don’t know how old the mill was but it was pretty well used. They powered the mill with an angle drill with the trigger locked on and plugged into a power strip. The routine was to reach under the mill and make sure the bottom roller was free. Then, flip the switch on the power strip to start the mill. Then, and only then, did you start pouring grain into the mill, and it worked best to pour slowly. Trying to fill the hopper before starting the mill always resulted in the grain filling the hopper with the top roller spinning away and no grain flowing through the mill.

The problem was always with the bottom roller. The store owner wasn’t too concerned about it; a minute or two of fiddling with the roller would, eventually, get the process started. I’ve always assumed that the bushings that the shaft for the roller turned in were worn and the gaps around the ends of the shaft were full of flour. It sounds like the OP’s mill is new. Perhaps it was assembled with the lower shaft in a bind.

 

[mongoose33]

I've got a(n) MM3.

I had some issues w/ the rollers not turning, then I figured out that somehow I had slightly misaligned the holes on the cabinet to which it's affixed. When I tightened them fully, they put a slight sideways pressure on the mill, and it would contribute to issues. Loosening them a skosh resolved the problem for me. I don't consider that a problem with the mill, but rather with the guy who installed it.

I wonder if the sideways torque that a pulley system creates also has a similar tendency if things aren't aligned correctly.

 

[RPh_Guy]

the bushings that the shaft for the roller turned in were worn

Sounds like it.

I always dump all the grain in the hopper before milling.

 

[mongoose33]

Sounds like it.

I always dump all the grain in the hopper before milling.

I do, too. I tried dumping the grain in after milling, but it didn't work as well.


What I do is turn it on, then start adding grain. I learned the hard way that if I fill up the hopper and turn it on and the rollers bind, I have to empty the thing before I can work on it.

Haven't had this problem since I figured out the overtight bolts holding it down, but habit dies hard. I start it, add a scoop of grain, and when it's clear that it's chewing through the grain, then I add the rest.

 

[SEndorf]

Sorry, have to ask:
The roller is turning the right way?

No apology necessary. I'm looking at anything and everything.
The mill shaft rotates clockwise. While I've never seen specific instructions for this, I assume the drive roller needs to spin "into" the top idle roller.
I'm almost wishing this was the problem.

From the helpful posts, I may need to loosen the mill mounting bolts, but the torque from the belt might make the alignment worse.

 

[RPh_Guy]

I assume the drive roller needs to spin "into" the top idle roller.

Yes, that's right.

My model isn't exactly the same as yours because mine has ball bearings instead of bushings. I do wonder if the lateral tension of the belt might be causing problems somehow. Any chance you could test it with a drill or hand crank?

As @Tobor_8thMan asked, you made sure to use the feeler gauge between the drive roller and the bottom roller?

Otherwise I'm out of ideas. You could try conditioning, which might help the rollers grip the grain, but that doesn't fix whatever the underlying problem is. And as mentioned you could try feeding the grain through slowly, though I haven't found that to be necessary.

Bummer, hope you get it fixed.

 

[Tobor_8thMan]

From my understanding, I do hope the following is accurate.

Drive Other
Roller Roller
Spins -> <- Spins

Bottom Roller
<- Spins

If the above diagram is accurate, and please let me know if it is incorrect, set the gap at the left between the Drive Roller and the Bottom Roller.

 

[tektonjp]

No apology necessary. I'm looking at anything and everything.
The mill shaft rotates clockwise. While I've never seen specific instructions for this, I assume the drive roller needs to spin "into" the top idle roller.
I'm almost wishing this was the problem.

From the helpful posts, I may need to loosen the mill mounting bolts, but the torque from the belt might make the alignment worse.

Had this problem. And I found that the instruction book from MM had the wrong advice (unless I misunderstood). Grain just sat on top, wouldn't feed thru. The problem is the gaps. Top gap is fixed. But you must make sure that the gap between the two non-drive rollers is smaller than the gap between the drive roller and the bottom roller. If the gap size gets switched around, the grain can't flow through. It gets hung up wanting to go out between the two non-drive rollers, and just sits there. You probably need to to do adjustments with the mill turned over.

 

[SEndorf]

The problem is the gaps. Top gap is fixed. But you must make sure that the gap between the two non-drive rollers is smaller than the gap between the drive roller and the bottom roller.

I'm not following this. While facing the mill with the drive shaft on the right, I put the feeler gauge through the bottom roller. (according to their video)
Can you explain your method that worked?

 

[SEndorf]

From my understanding, I do hope the following is accurate.

Drive Other
Roller Roller
Spins -> <- Spins

Bottom Roller
<- Spins

If the above diagram is accurate, and please let me know if it is incorrect, set the gap at the left between the Drive Roller and the Bottom Roller.

That's how MM video says to do it.

 

[hottpeper13]

I was a MM in the Navy and a Millwright after that. Installed pumps and motors and other stuff. You must have a pillow block bearing on the out side of the pulley on the mill to keep the shaft from flexing!!!!!!!!!!!!!! If you don't do this and you get the mill to work,eventually it will destroy the bushing on the mill.

 

[SEndorf]

I've got a(n) MM3.

I had some issues w/ the rollers not turning, then I figured out that somehow I had slightly misaligned the holes on the cabinet to which it's affixed. When I tightened them fully, they put a slight sideways pressure on the mill, and it would contribute to issues. Loosening them a skosh resolved the problem for me. I don't consider that a problem with the mill, but rather with the guy who installed it.

I wonder if the sideways torque that a pulley system creates also has a similar tendency if things aren't aligned correctly.

I mounted the mill into 3/4 plywood. Measured and marked a half dozen times then drilled. The mounting holes are the width of the bolts and exactly line up. Maybe that's the problem. I noticed the mounting board that comes with the mill has quite large holes. Perhaps to allow some alignment wiggle room?
But if I loosen the mill mounts with the belt on, everything will go sideways... figurative and literally.

 

[SEndorf]

I was a MM in the Navy and a Millwright after that. Installed pumps and motors and other stuff. You must have a pillow block bearing on the out side of the pulley on the mill to keep the shaft from flexing!!!!!!!!!!!!!! If you don't do this and you get the mill to work,eventually it will destroy the bushing on the mill.

I had to google "pillow block bearing". Makes sense. This is getting way more complicated. Might be time to go to plan B. Just need to figure out what plan B is.

 

[SEndorf]

As an experiment, I removed the belt and tried a drill. Same result. Spinning but no milling.
It will crush grain if I slowly sprinkle a handful in.

 

[kh54s10]

Not a MM, but my mill stopped once and after looking at it there was a very slight difference in the gap from one end to the other. I think you have something out of alignment somewhere. It probably will just take some more adjustments. Maybe start from scratch - loosen and move everything then carefully tighten all the mounts etc, then the gaps and make sure everything is properly tightened.

 

[LittleRiver]

...At first the mill just locked up, but didn't stall the motor....Now the mill spins but doesn't feed the grain through...

I'm stumped about what the problem is with your mill.

I used an MM3 for years at the LHBS... reach under the mill and make sure the bottom roller was free. Then, flip the switch on the power strip to start the mill. Then, and only then, did you start pouring grain into the mill...

... I fill up the hopper and turn it on and the rollers bind, I have to empty the thing before I can work on it.... I start it, add a scoop of grain, and when it's clear that it's chewing through the grain, then I add the rest.

My first and only mill is a Kegco 3roller, driven with a 1/2" drill. I've had it 3+ years, with a gap setting of .025". I always completely fill the hopper before starting the drill. It has worked flawlessly each and every time. I didn't realize how fortunate I've been in that regard. I don't say that to brag, it's just that I'm stumped about what caused the OP's problem, and I'm surprised to hear these problems with the MM3 (which I've always had the perception of being an even better mill than what I have).

 

[Tobor_8thMan]

.025"? This is very fine. Didn't this produce flour from the grain?

 

[tektonjp]

I'm posting a diagram because I'm a visual guy. I'm guessing your situation is the top drawing. The grain is drawn in, but is basically sitting in the center chamber churning around. Why? There's a gap it could go through. BUT, IDLE 1 has no power to overcome the opposing direction of IDLE 2. Whe you reverse that situation to the bottom drawing, the grain feeds through because the drive roller is powering the idle rollers in the correct direction and the grain is encouraged to flow through the larger gap.

IDLE 2 has eccentric adjustments. You need to not only set the gap it has with the drive roller, but also make sure that the resulting corresponding gap between 1 and 2 is less than. Because it is possible to set your desired gap between Drive and IDLE 1 and have the gap between 1 and 2 be the same size or larger, double check. And as a poster said above, it is also important that the gap is even across the rollers.

Make sense?

 

[schematix]

I had a ***** of a time setting up my MM3-Pro when i got it. Turned out the solution was to not tighten the bolts. They're a bit more than finger tight. That plus a little wiggling until the rollers spun freely and it works great. Their hopper also has a tendency to put the base into a bind. Not a single screw or bolt in the entire thing is tight otherwise it binds right up.

 

[SEndorf]

I've tried adjusting, re-adjusting, tightening, loosening....
I'm throwing in the towel on the MM3.
I've made great beer with a 2 roller mill. Guess that's my plan B.
I'm no stranger to motorized grain mills, but not arrogant enough to still consider it's some sort of setup error on my part, but this is thing is just too finnicky. Not worth tearing my hair out over. (what little is left)….
I REALLY appreciate the responses and help here.
Thank you all !

 

[day_trippr]

I'm surprised a three roller mill can actually be set up so wrong per the diagrams above. Can't be helpful to end users.
While I haven't aspired to a three roller mill this thread makes me happy I went with the CK two roller mill when I replaced my well-used BC...

Cheers!

 

[SEndorf]

I'm surprised a three roller mill can actually be set up so wrong per the diagrams above. Can't be helpful to end users.
While I haven't aspired to a three roller mill this thread makes me happy I went with the CK two roller mill when I replaced my well-used BC...

Cheers!

This project is also replacing a worn out BC.
Haven't decided yet if I'm going to a MM2 or a CK.

 

[rustbucket]

might want to check if there is dust build up at the ends; if you did not buy a hopper and built one; the dust builds up at the ends; most hoppers have a direction to push the grain about 1/2in to 1 in away from where the bearing are to keep the dust out. i had this issue where the dust would get in there and create a paste and lock the rollers up

 

[SEndorf]

Thanks rustbucket, but this is brand new and I'm using the MM hopper.
I've wasted enough grain testing this beast. It's time for me to move on.

 

[mongoose33]

I've tried adjusting, re-adjusting, tightening, loosening....
I'm throwing in the towel on the MM3.
I've made great beer with a 2 roller mill. Guess that's my plan B.
I'm no stranger to motorized grain mills, but not arrogant enough to still consider it's some sort of setup error on my part, but this is thing is just too finnicky. Not worth tearing my hair out over. (what little is left)….
I REALLY appreciate the responses and help here.
Thank you all !

One more suggestion for you: Assuming you can remove the pulley and get it down to just the roller shaft, have you tried using a drill to power this, i.e., taking off the sideways pressure the pulley system produces? If you do that and you still get binding after adjustment, then it's the mill that's the problem. If the problem goes away, it's the use of a pulley system that is the culprit (somehow).

And: I can't recall who manufactures the MM3, but have you contacted them about this? Maybe the specific unit you have is defective.

 

[Jtvann]

Well I for one am glad this thread was started. I bought a MM3 a few years ago and recently upgraded from 5 to 10 gallon batches. My drill was a cheapy and started over heating on the bigger grain bill. I motorized mine, but the exact problem that you describe staryed happening to me. I'd have to reach under the mill and spin the bottom roller by hand with the motor running to get it going. Always envision being eaten by the damn thing when I do that. Loosened up the bolts and now it's working like a charm.

Thanks all

 

[kh54s10]

I would suggest contacting Monster Brewing hardware.. There may be a defect in your mill. They may have suggestions to lead you to the problem.

MM is one of the most highly respected mills made. Your problem is not typical.

 

[SEndorf]

One more suggestion for you: Assuming you can remove the pulley and get it down to just the roller shaft, have you tried using a drill to power this, i.e., taking off the sideways pressure the pulley system produces? If you do that and you still get binding after adjustment, then it's the mill that's the problem. If the problem goes away, it's the use of a pulley system that is the culprit (somehow).

And: I can't recall who manufactures the MM3, but have you contacted them about this? Maybe the specific unit you have is defective.

Yup. See post 20.
This is my second one. I returned the first one to MoreBeer who were very nice about it.
On the first one, right out of the box, with the set thumb screws tightened all the way, I could still freely turn the gap adjusting knobs.

 

[SEndorf]

I did contact Monster Brewing Hardware and exchanged messages with Fred.
He gave me some suggestions, same as the posts here.

 

[CodeSection]

@SEndorf, perhaps I missed it in a post somewhere, but you are adjusting the gap on both sides of the bottom roller, correct? It appears others had experienced similar issues until they set the bottom roller to the lowest point possible and then adjusted from there. Not that .008 should make a difference, but the MM-3 video on their website suggests starting out with a .022 + .018 = .040 gap size.

https://www.monsterbrewinghardware.com/store/pc/MM-3-p86.htm

https://www.homebrewtalk.com/forum/threads/3-roller-monster-mill-help.255840/

I realize you are frustrated, but I wouldn't give up quite yet. What are the odds of receiving two faulty MM-3? Maybe MB received a bad manufacturing batch if ultimately that is the issue. When you received the second MM-3, was it in a sealed box? MB accidentally sent me a returned bench bottle capper. They quickly rectified their mistake. MB is a great company and will work with you, even if it means sending you another MM-3.

I have the MM-3Pro and it performs flawlessly.

 

[wilserbrewer]

Be sure the rollers have some play in the end blocks and are not binding.

Be sure to set the gap between the driven roller and the bottom roller properly.

Monster has a you tube video on this ....it’s critical.

Again, if the mill side plates on the roller are tight, the mill will bind, perhaps this is why the factory base has oversized holes. The rollers should have some slack or space within the end blocks of the mill....important!!!

 

[schematix]

I've tried adjusting, re-adjusting, tightening, loosening....
I'm throwing in the towel on the MM3.
I've made great beer with a 2 roller mill. Guess that's my plan B.
I'm no stranger to motorized grain mills, but not arrogant enough to still consider it's some sort of setup error on my part, but this is thing is just too finnicky. Not worth tearing my hair out over. (what little is left)….
I REALLY appreciate the responses and help here.
Thank you all !

Almost guaranteed to be an error on your part, but i agree with your sentiment that its difficult to set up. I am mechanically and technically inclined and i pissed away a lot of my time getting it just right.

IMHO their fail is that they should provide a metal base plate to align the frame pieces they provide, and that base plate should be independently attached to whatever. Also what for what they charge some real bearings instead of bushings would be nice.

 

[LittleRiver]

.025"? This is very fine. Didn't this produce flour from the grain?

Yes, it produces a lot of nice flour, which I use with my single vessel BIAB rig to get a brewhouse efficiency of ~83%. That's with no sparging, no re-circulation. If you think the beer comes out cloudy, or has taste problems, that is not the case.



No finings of any type were used in that beer, just a cold crash for a few days after fermentation.

 

[augiedoggy]

I was a MM in the Navy and a Millwright after that. Installed pumps and motors and other stuff. You must have a pillow block bearing on the out side of the pulley on the mill to keep the shaft from flexing!!!!!!!!!!!!!! If you don't do this and you get the mill to work,eventually it will destroy the bushing on the mill.

Yes I second this... MM sells an upgraded version of the 2 roller pro mill with bearing for belt driven applications... its only like $400 plus shipping with the hopper.. Or you could just have bought the $150 kegco 3 roller with ball bearing but its a bit late for that now..
Dont take this the wrong way but I have a feeling though that if you had bought the kegco you might still have this problem if it is self induced somehow and everyone would be blaming on the "cheap" chinese mill. As they did in another recent thread that sounds like op had similiar issues with the kegco.

For what its worth I have the 3 roller kegco and have the rollers/gap as far open as they will go because of a very poorly designed false bottom in my 3bbl mash tun I need to replace. We do still manage an average of 85% efficiency though.