# Monster Mill Problems



## pbrosnan (12/7/09)

Hi all,

Been using my 2 roller MM for about 12 months (12 or so brews). All was fine up until last brew. I started up the motor and began to fill the hopper. I quickly noticed that the level of grain in the hopper wasn't dropping. After some investigation (i.e. taking off the hopper and sundry bits of my crappy carpentry) I found that the grain wasn't being pulled into the rollers. 
With the motor running at normal rpms the grain just bounces around on the rollers, the non-powered roller doesn't turn at all although it will turn when pushed by hand so it's not obstructed or seized. The strange thing is I haven't changed anything, it started happening out of the blue. I've fallen back to my drill powered Marga which hasn't missed a beat in over 40 brews. The MM was a replacement for the Marga but after spending 2 hours this arvo fiddling with the gap and stripping the whole thing and still not getting anywhere I'm thinking I may be better off motorising the Marga. 
Has anyone else had anything similar happen?

cheers

Patrick.


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## warrenlw63 (12/7/09)

Patrick

I have the same mill. Just sounds like a simple obstruction in the idle roller. Maybe pull the mill apart and clean and/or oil the bushings on the idle roller?

It's probably less of a problem than you think. If the idle roller is not spinning "very" freely then it won't work.

FWIW what's your gap set at?

Edit: I don't want to sound like I'm insulting your intelligence but is the powered roller spinning in the right direction? ie; towards the idle roller?

Warren -


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## clatty (12/7/09)

pbrosnan said:


> Hi all,
> 
> Been using my 2 roller MM for about 12 months (12 or so brews). All was fine up until last brew. I started up the motor and began to fill the hopper. I quickly noticed that the level of grain in the hopper wasn't dropping. After some investigation (i.e. taking off the hopper and sundry bits of my crappy carpentry) I found that the grain wasn't being pulled into the rollers.
> With the motor running at normal rpms the grain just bounces around on the rollers, the non-powered roller doesn't turn at all although it will turn when pushed by hand so it's not obstructed or seized. The strange thing is I haven't changed anything, it started happening out of the blue. I've fallen back to my drill powered Marga which hasn't missed a beat in over 40 brews. The MM was a replacement for the Marga but after spending 2 hours this arvo fiddling with the gap and stripping the whole thing and still not getting anywhere I'm thinking I may be better off motorising the Marga.
> ...



Hey Patrick

I just motorised my MM3 and found that I had the mill sides too tightly screwed to the bench and the non-powered roller would not turn smoothly (i had to loosen the screws and tap the sides out with a rubber mallet, see pic). As Warren said there maybe something obstructing the roller as yours worked ok before... How freely does the non-powered roller move by hand? Good luck with it.


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## pbrosnan (12/7/09)

warrenlw63 said:


> Patrick
> 
> I have the same mill. Just sounds like a simple obstruction in the idle roller. Maybe pull the mill apart and clean and/or oil the bushings on the idle roller?
> 
> ...



Hi Warren,

Thanks for the reply. No need to worry about insults to intelligence and the powered roller is spinning the right way. I took the idle roller cams off and sprayed a bit of silicon lube in which didn't seem to make much difference. Do you know if the idle roller is sitting on a bearing? I'll continue to try and fix it via the idle roller then. Gap has varied a bit this arvo, I think it's at about 0.9mm ATM.

cheers

Patrick.


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## pbrosnan (12/7/09)

clatty said:


> Hey Patrick
> 
> I just motorised my MM3 and found that I had the mill sides too tightly screwed to the bench and the non-powered roller would not turn smoothly (i had to loosen the screws and tap the sides out with a rubber mallet, see pic). As Warren said there maybe something obstructing the roller as yours worked ok before... How freely does the non-powered roller move by hand? Good luck with it.
> 
> View attachment 28794



Hi Clatty,

It could spin more freely. If I give it a push it probably stops within a 2-3 seconds. I don't know what it was like before it stopped working. I hate wasting of grain trying to fix it.


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## Zwickel (12/7/09)

Patrick, I had the same issue with mine.
After I had milled around 100kg of grain, the roller had lost its grip and the idle roller was still standing, no grain went through.
What Warren says, helps a little while, but in my case it came again and again and got really anoying.

In the end, I had only two chances, either way ditch the whole mill or synchronize the rollers.

I decided to go the second way.

What I did: just cut two cogwheels out of a piece metal sheet:




made a distance holder like that:




and mount it behind the rollers:







voil, the mill runs again, no more worries.

Cheers :icon_cheers:


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## Vlad the Pale Aler (12/7/09)

I have an MM3 which I bitterly regret buying, like yours it fails to perform on occasion without any reason at all.
I stripped the thing down and cut a slot in the end of the idle roller with an angle grinder, I use this to "kickstart" the mill with a screwdriver when it stalls.
The knurl on the rollers seems too smooth to pull the grain in so I reduced the intake opening in the hopper which helps,( I would post some pics but its cold in the shed and this 80/- is too good to leave alone).


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## pbrosnan (12/7/09)

Hi Zwickel,

Beautiful job but probably beyond my skills as a metal worker. I would be easier to motorise the Marga. It does sound like we have the same problem though. I was wondering if there was a way of re-roughing the roller surfaces to see if I could get it to grab the grain more positively.


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## RobW (12/7/09)

I have the same mill and it's done that a couple of times recently.
I found it was one of the thumbscrews vibrating loose and opening up the gap a little.
If I tighten the thumbscrew it's OK for a while then slips again.
Probably needs a bolt or a screw instead of the thumbscrew so I can tighten it a little more.


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## Zwickel (12/7/09)

pbrosnan said:


> ...I would be easier to motorise the Marga. It does sound like we have the same problem though. I was wondering if there was a way of re-roughing the roller surfaces to see if I could get it to grab the grain more positively.



Patrick, my mill is motorized, that doesnt change the problem.
In the first time I could help myself by increasing the gap to 1.8mm and mill again a second time by setting the gap to 0.8mm
That worked well for a certain time, but then the problem started again.

I even changed the rollers three times, have the third set of rollers meanwhile. All of them showed the same issue.

I really have been close to sledgehammer the mill.

Fortunately, finally Ive found the solution, inspired by the Mashmaster Mill.

Cheers :icon_cheers:


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## pbrosnan (12/7/09)

Hi all,

I'm surprised by the number of people reporting this behaviour. It appears without radical modification ala Zwickel that the unit exhibits poor performance after a reasonably small number of brews (in my case about 10 or 12)? I probably can't use your solution Vlad as the way I have it setup I don't have easy access to the rollers. I tighten the thumbscrews with a pair of pliers as I had the loosening problem so its not the gap slipping and anyway I tried a lot of different gaps and have seen very little change. This is a great disappointment as it was milling 6kg in about 3 minutes. The only problem I had prior to this was not enough torque from the motor and like you Vlad I added a choke to the hopper to slow down the feed.


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## pbrosnan (12/7/09)

Zwickel said:


> Patrick, my mill is motorized, that doesnt change the problem.
> In the first time I could help myself by increasing the gap to 1.8mm and mill again a second time by setting the gap to 0.8mm
> That worked well for a certain time, but then the problem started again.
> 
> ...



Hi Zwickel

Did you get new rollers from the manufacturer or did you make them up? And just to be clear, you think the problem was with the knurling on the rollers and the mill having to rely on the knurling to turn the idle roller?


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## Thirsty Boy (12/7/09)

Have you tried varying the speed of the mill? I know that if mills run too fast, they can bounce the grain around without pulling it in. Vlad also mentioned reducing your hopper opening. Reducing the flowrate of grain in also helps to smooth out feeding issues in mills.

Also, a bit of a wire brushing of the rollers might help - the knurling might have lost a little of its edge which was previously helping to drag the grain in -- worn off a little its no longer doing the job. A bit of a brush up might give it back a little bite.

Also, a low tech way to get an active #2 roller is to put an o'ring onto the driven roller that gets squashed up against the passive roller - this spins the passive roller, not with enough force to do anything much, it is still "crushing" the grain a passive roller, but it helps with dragging the grain into the mill.

I have the MM 2 and have yet to experience any issues -- but I tend to run my mill quite slowly (120-150 rpm or slower) -- I don't know if this is one of the reasons mine is still working well, if I have just been lucky so far, or if you guys have just been unlucky.

TB


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## Online Brewing Supplies (12/7/09)

pbrosnan said:


> Hi Zwickel
> 
> Did you get new rollers from the manufacturer or did you make them up? And just to be clear, you think the problem was with the knurling on the rollers and the mill having to rely on the knurling to turn the idle roller?


I will post a solution to you by email/PM.Its a bit of work but doesn't involve any mechanical reworking.
GB


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## kram (12/7/09)

I've done 35 or so batches with mine now, after about 25 it stopped pulling through. I think the gap just closed up a little; it made me get off my arse and finally build a proper stand and hopper for it. Put it back together, reset the gap and it's been going fine. Only once i've had to tap the idle roller to start it spinning to get the crush going.


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## pbrosnan (12/7/09)

Thirsty Boy said:


> Have you tried varying the speed of the mill? I know that if mills run too fast, they can bounce the grain around without pulling it in. Vlad also mentioned reducing your hopper opening. Reducing the flowrate of grain in also helps to smooth out feeding issues in mills.
> 
> Also, a bit of a wire brushing of the rollers might help - the knurling might have lost a little of its edge which was previously helping to drag the grain in -- worn off a little its no longer doing the job. A bit of a brush up might give it back a little bite.
> 
> ...



Hi TB,

Yeah tried varying the speed to no avail. I will try roughing the knurling up again and see if that makes a difference. I'm interested in the 'O' ring idea but no quite sure how to go about it. Don't suppose anyone has done anything like that (not you Zwickel, looking for cheap and cheerful)? As I see it the problem would go away if I could just get the idle roller spinning, a bit like the crank handle on an old motor.


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## Zwickel (12/7/09)

pbrosnan said:


> Did you get new rollers from the manufacturer or did you make them up? And just to be clear, you think the problem was with the knurling on the rollers and the mill having to rely on the knurling to turn the idle roller?


Ive got the new rollers from manufacturer. The first 100kg of malt the mill worked a treat, no problems at all and the malt went through very quick.
But then it started to make troubles. First I didnt know at all what the heck the problem is, bcause I couldnt see the idle roller.
Later then, I realised its the idle roller that makes the trouble.

okay, first few times I could help it by cleaning the rollers (have brushed it) and it worked again for the next 10kg, then the problem started again.
Then I had to brush the rollers after 8kg, then after 6kg and so on. In the end I couldnt get even one kg through.

It seemed to me as the metal of the rollers would be too soft and the grip was fading.
The knurls of the new rollers have been very sharp, but after a little while it became blunt.

So I guess the metal is not hard enough.

Cheers :icon_cheers:

edit: spelling


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## glaab (13/7/09)

I been thinking of buying one when I win the lotto but I'm having second thoughts after reading this thread. My little Marga is looking better all the time. I read somewhere that dampening the grain
will help it go through, IIRC it was about 50ml per kg, have you tried that?


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## Zwickel (13/7/09)

glaab said:


> .... I read somewhere that dampening the grain
> will help it go through, IIRC it was about 50ml per kg, have you tried that?


thats certainly right, but the rollers are not made of SS, so I afraid they will be rusting.

Cheers mate :icon_cheers:


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## AndrewQLD (13/7/09)

Gryphon Brewing said:


> I will post a solution to you by email/PM.Its a bit of work but doesn't involve any mechanical reworking.
> GB



Hey GB, how about sharing the love and posting your solution here?  There could well be a few other brewers who could use your advice at some stage in the future.
I've got the MM2 and have crushed about 200 kg++ and haven't had an issue YET, but you never know what will happen, I for one would be interested in a non mechanical fix.

Cheers
Andrew


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## Screwtop (13/7/09)

Have a MM3 and mill grain for 25 - 30 brews each year. Had this problem a couple of times early on when I started milling for double batches, here is what I have done since without a problem. Start the mill running (I use a variable speed drill with revs set low), then tip a small amount of grain into the hopper to get the rollers going, add a little more and then add the remainder. It seems a lot of grain weight pressing on the rollers may make the it difficult for the idle roller to turn in the bush after sitting for some time. I usually give them a spin prior to milling anyway, but when the hopper is full sometimes if you miss the start and don't get the idlers going, then you have to tip out the hopper and start over. Have tried a few other methods, this works for me, be sure the mill is running then tip in a cupfull or so, slowly add to this to keep the rollers turning then add the remainder.

Rollers/knurling is cleaned periodically, imagine some fine grain dust finds it's way into the bushes so not surprised the mill doesn't run like it did when new. Overall very happy with mine.

Screwy


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## warrenlw63 (13/7/09)

clatty said:


> I had the mill sides too tightly screwed to the bench and the non-powered roller would not turn smoothly



I think clatty has a genuine solution here also. When I attached mine to a base this happened early on. If the sides are not perfectly at 90 degrees the idle roller will stick. Tighten the bolts so they are "just" tight enough.

Warren -


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## clean brewer (13/7/09)

Screwtop said:


> Have a MM3 and mill grain for 25 - 30 brews each year. Had this problem a couple of times early on when I started milling for double batches, here is what I have done since without a problem. Start the mill running (I use a variable speed drill with revs set low), then tip a small amount of grain into the hopper to get the rollers going, add a little more and then add the remainder. It seems a lot of grain weight pressing on the rollers may make the it difficult for the idle roller to turn in the bush after sitting for some time. I usually give them a spin prior to milling anyway, but when the hopper is full sometimes if you miss the start and don't get the idlers going, then you have to tip out the hopper and start over. Have tried a few other methods, this works for me, be sure the mill is running then tip in a cupfull or so, slowly add to this to keep the rollers turning then add the remainder.
> 
> Rollers/knurling is cleaned periodically, imagine some fine grain dust finds it's way into the bushes so not surprised the mill doesn't run like it did when new. Overall very happy with mine.
> 
> Screwy



Im the same as Screwy, I dont have a MM3 but a Home Made job with 2 inch rollers and not a course knurl, only 1 roller is powered by a 2 speed drill so the other roller is free spinning... When I first started using it, I would load the hopper up with 5kg of Grain, start the drill and nothing would happen(pain in the arse :angry: ), even tried wetting the grain and still nothing... I would have to try move the stationary roller with my hand to catch some grain between the 2 to get the rollers started... Still didnt work...  

So, I 1 day just put in about 500gr of grain and started the drill and yippy  , the grain started milling, once it had started I would fill the hopper and it would keep pulling it through no worries.. Have had no dramas since with doing it this way and as Screwy said, the grain load on the rollers was too much and would just jump around and not pull through..

So, maybe just try that???????????

:icon_cheers: CB


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## Thirsty Boy (13/7/09)

you guys have it I reckon - I never thought of that. I guess I am doing something similar. I use a cordless drill on the low gear setting, and while I start with my grain hopper full... I get things going by just running the drill - less than 60rpm - which drags some grain in, then once I hear it crushing properly, I ramp the speed up.

I also have an old water cooler bottle as my hopper - so its not full width on the mill. So there isn't a hell of a lot of grain sitting on the rollers and a few stray ones at the side can work their way down into the gap and get things rolling.

TB

edit - spelling


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## Hubby (13/7/09)

My Marga mod / home made version died yesterday ... p!$$ed off to say the least. I was about 80% through! Has anyone heard back from MM re these problems? I was thinking about buying one - if I sell my 4WD - but I might have to wait :unsure:


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## Midnight Brew (8/11/12)

I'm so glad this thread exists. I've just spent close to 45 minutes cracking the shits with my mm3 thinking why the hell isn't it milling. The answer was in the thread. Just needed to be loosened where the mill is attached to the base and holy snappin duck shit it worked. Relief.


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## CONNOR BREWARE (8/11/12)

I didn't know this thread did exist but had the same problem from the very first attempt. However I loosened the thumbscrews a little and that fixed it with a full 10kg of gran sitting on top. Mind you that's over a small area of feed in, about 2 inch diameter. I also run a slow 100 RPM to start with then ramp up to my max of about 160.

After reading all the other responses I think I'm bound to have the same issue again but hopefully not.

Zwickel has your solution stood the test of time?

cheers

Ciro


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## potof4x (9/11/12)

I exclusively have problems with my mm3 after I turn it upside down to brush off the rollers. Any grain material against the non driven rollers will cause it to jam when trying to start. It will not necessarily be immediately after cleaning as some material can lurk up in the hopper, and rattle down through a few uses. If I don't turn upside down = no problem.


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## komodo (12/11/12)

Frame needs to be properly square.

Edit - how I resolved my issues :
http://www.aussiehomebrewer.com/forum/inde...c=58713&hl=


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## Diesel80 (12/11/12)

My problem recently has been one of the thumbscrews were coming loose and whole grains were dropping through as the 2nd roller became off square.

Reset and tightened with pliers. 

Last brew day, worked for about 50% of the hopper. Had to flick drill in reverse then back into normal running to do the rest of the grain. The 2nd roller just stops at certain times during milling with a small gap for BIAB. I think it is getting jammed. The reverse trick, well does the trick. 

I have MM2.0 stainless and drive it with an Ozito Spade Handle drill (recommended drill motor it owns! - so long as chuck is tightened sufficiently).

Cheers,
D80


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