Question on 2 roller grain mills

[Bill Huelsman]

I have a cereal killer 2 roll grain mill, had it for a few years now. Another club reached out for 3 extra brewers needed for a RIS, with a 22 lb grain bill to go into a freshly emptied bourbon barrel.

In the two years I’ve had this, the one roller not driven by the handle/drill, would sometimes not spin. I make it a point now to check it before using.

Yesterday while going to brew the RIS, it would not grind up the Golden Promise malt to save my life! My brother popped by, and if he kept going back n forth over the top of the rollers with the feeler guage, it would grind. Stop and the mill quit grinding. Start up again and it would continue to work. Fought me for over two hours! There were a total of 6 malts in the grain bill, the GP was 18 lbs of it. I’m sure there are allot of us with this mill, curious to see if anyone else has had this problem before.

 

[smyrnaquince]

I have a new Cereal Killer. I noticed that if I tighten the lock screw down too hard on the adjustable roller, it does not spin freely.

 

[robcj]

View attachment 664033 View attachment 664033 Yesterday while going to brew the RIS, it would not grind up the Golden Promise malt to save my life! My brother popped by, and if he kept going back n forth over the top of the rollers with the feeler guage, it would grind. Stop and the mill quit grinding. Start up again and it would continue to work. Fought me for over two hours! There were a total of 6 malts in the grain bill, the GP was 18 lbs of it. I’m sure there are allot of us with this mill, curious to see if anyone else has had this problem before. View attachment 664032

I’ve gone through two mills like this (different names but identical designs) and this happened to both. The first lasted a couple of years before it stopped working and the second barely made it a year. I completely disassembled and cleaned them many times but the free roller would just stop catching grain. Increasing the gap would help but came with obvious and eventually untenable compromises. So frustrating—ruined a few brew days for me.

I can't be sure but I think it was the knurling wearing down on the lower quality steel rollers. (Maybe I was wearing them down faster because I was driving them too quickly? Some people have this problem—there are dozens of threads on various forums—but others don’t.)

I upgraded to a two-roller Monster Mill. I certainly expected an improvement but I was shocked by the difference in quality. The rollers are much larger and the steel looks and feels like it is way higher quality. The knurling feels way sharper. It’s a distinct upgrade that chews through grain without pause and I regret wasting money on cheaper alternatives. (All that said, my buddy has been using the same $30 corona mill for almost ten years and never had an issue...)

 

[augiedoggy]

if you have the cereal killer its most likely not knurling wear. are you sure the 2 cams arent 180 degrees out of phase? You can actually still get an even gap this way with a feel guage but the roller is cocked slightly up and down on an angle causing it to sometimes bind and stop. I had this issue too when I first got my CK 6 years ago.. once I understood what was wrong and adjusted it correctly the issue went away.

Also having the mill cranked down too hard to a piece of wood can also causebinding between the end of the roller and frame.. Theres many threads with Monster mills also where this is the complaint.

I have the 3 roller version of the cereal killer mill (kegco branded) at my brewpub and its had over 10,000 lbs of grain milled through it so far and the knurling still looks fine. We drive the mill at 170rpm with a bodine gear reduction motor and in my experience the real ball bearings the cereal killer and other branded mills from the same supplier has goes a long way over the cheap bronze bushings some mills use which wear much quicker and cause slop as well as rolling issues. The ball bearings are large step up in price through some mill makers.

If you have the barley crusher brand mill your issues are likely worn knurling as its a very common complaint on that mill.

 

[DVCNick]

I have a Barley Crusher (yeah, I know.... no one mentioned it was the crappiest one in my thread on the subject until after I ordered).

I've had this problem as well, but I think mine is way too new for it to be worn knurling.

Actually I know know exactly what caused it. When I got it, there was a rubber o-ring around the driven roller. It would just slightly engage the other roller and cause it to want to spin too. For some reason I didn't really pick up on this until after my first session where I couldn't get any grain to go through it, and then after I emptied it out, the light came on in my head... the o-ring had broken and there was absolutely nothing driving the other roller.

In my case, as long as I don't fill the hopper more than halfway, it keeps moving without the o-ring. I run into problems with no o-ring and full hopper. I haven't motivated myself enough to take it apart and put on a new o-ring, but I'm sure the day is coming (once the knurling is actually worn down a bit), and having to do that every few batches is going to be irritating. They should have some sort of gear driven linkage between the rollers, would have been easy and foolproof.

 

[Robert65]

Most mills (even commercial) have only one driven roller. The free roller is driven by the feeding of the grain itself. An o-ring will only interfere with adjusting the gap.

 

[augiedoggy]

as mentioned mills like the cereal killer don't even come with this oring... the grain itself drives the non directly driven roller.

 

[bracconiere]

lol, i remember the o-ring on my JSP Malt Mill......lasted like one session.....now i use a knife on the non driven one if it stops engaging, just stick it in, and get it crushing again....also sometimes i can use a long spoon through the hopper to get it to catch....

 

[Robert65]

lol, i remember the o-ring on my JSP Malt Mill......lasted like one session.....now i use a knife on the non driven one if it stops engaging, just stick it in, and get it crushing again....also sometimes i can use a long spoon through the hopper to get it to catch....

I had a JSP back in the day, and I still have the instructions on file. The o-ring was installed to "facilitate assembly and checkout," and was to be removed before use. It was explicitly stated that the free roller was to be driven by the friction of grain. IOW it was just like every other 2 roller mill in operation. They should not have an o-ring in place during operation.

 

[bracconiere]

The o-ring was installed to "facilitate assembly and checkout," and was to be removed before use.

you mean i would have had to taken it apart? lol, i guess i could have cut it....but using the mill removed it real fast anyway!

 

[tellyho]

I am a many-year owner of a Cereal Killer, 12 batches a year. Early on in my ownership, I used my air compressor to clean out the mill. The CK uses "sealed" bearings on the rollers. They are of middling quality (at least from a bike mechanic point of view) and can be contaminated with grain dust fairly easily. My non-drive roller quickly became hard to turn and I had to replace the bearings. Perhaps this is your problem.

 

[day_trippr]

I've read of ^that^ problem and switched to using my shop vac on the mill. But I also have been conditioning my grain for the last few years which dramatically cuts the apparent dust - though I don't know for sure that matters...

Cheers!

 

[augiedoggy]

I am a many-year owner of a Cereal Killer, 12 batches a year. Early on in my ownership, I used my air compressor to clean out the mill. The CK uses "sealed" bearings on the rollers. They are of middling quality (at least from a bike mechanic point of view) and can be contaminated with grain dust fairly easily. My non-drive roller quickly became hard to turn and I had to replace the bearings. Perhaps this is your problem.

I believe you mentioned this before or maybe it was someone else but this is only the second report Ive ever seen myself of someone having this issue with the bearings on these mills and Ive read every mill thread Ive come across here.
I'm guessing the bearings either changed or the quality varies from unit to unit and I got lucky on both my mills as ive never had to clean them and havent yet had the issue. I would think If anything the 3 roller kegco at the brewpub would see these problems as its used to mill around 200lbs of grain every sunday for over a year now with the exact same bearings. Ive never conditioned my grain even with the 6= year old CK at home. The sealed bearing hold up much better than cheaper built mills that use bronze buchings that quickly wear and become impacted with grain dust causing the mill to constantly have to be disassebled and cleaned or the bushings replaced. This is why MM offers real bearings on thier $600> pro series mills as an option.

In case anyone didnt know here the Cereal killer, Kegco, Malt munchier, morbeer's evil twin and northern brewers Hull wrecker are all from the same manufacturer in china. The factory will brand and package them with whatever name you want if you place a large enough order.. they will even cnc the logo in the side for you for a small fee now.

I have to believe things like milling rpm have a dramatic effect on wear as well because I know of one person who claims the rollers on one of these mills has worn out... Well we drive ours at a steady 170rpm with a gear reduction motor and even after over 10,000lbs of grain being milled through it, the rollers knurling still looks new. We still have a new mm3 sitting in the box as backup but im really curious to see how well it will hold up with the same use.
Perhaps the speed is also a factor in why some have more issues with the second roller grabbing and turning consistently?

 

[DVCNick]

Interesting. Well I didn't have any issues adjusting the Gap and it sure worked better with the o-ring in one piece. I'll just keep dribbling in the grain I guess.

 

[augiedoggy]

Interesting. Well I didn't have any issues adjusting the Gap and it sure worked better with the o-ring in one piece. I'll just keep dribbling in the grain I guess.

you can also try disassembling and flipping the roller around which some claimed works well to get additional life out of the BC because of the way the knurling wears and points.... I would look at the bushings for grain dust and wear which often causes the rollers to stick. many local hardware stores sell the correct replacement bushings as they are like the type sometimes used in cheap particle board furniture for hinges. resist the urge to use any oil on any of these mills bearings or bushings. it will only cause more problems down the road.

 

[augiedoggy]

you mean i would have had to taken it apart? lol, i guess i could have cut it....but using the mill removed it real fast anyway!

I believe I read in another thread that JSP intended it to just break away with normal use as yours did.

 

[DVCNick]

It has probably less than 10 batches of total use and both rollers spin freely. In terms of cleaning I just blow all the dust out with a handheld blower and then wipe down the outer surfaces with a slightly damp cloth.

 

[augiedoggy]

It has probably less than 10 batches of total use and both rollers spin freely. In terms of cleaning I just blow all the dust out with a handheld blower and then wipe down the outer surfaces with a slightly damp cloth.

are you using a drill with it? Maybe try slowing the crush speed down. these mills have an ideal suggested rpm of like 180 to 250 rpm if I rememeber right.

 

[DVCNick]

Yes. I run it pretty slow; on the low speed/high torque setting and then only at about half throttle. Not sure what the RPM is, but its pretty slow.

When it jams however; doesn't matter what speed it is going, nothing happens until I stick a rod or something in there to turn the non-driven roller a little bit and get it going again, or empty out the hopper and fill it to ~half full.

 

[augiedoggy]

Yes. I run it pretty slow; on the low speed/high torque setting and then only at about half throttle. Not sure what the RPM is, but its pretty slow.

When it jams however; doesn't matter what speed it is going, nothing happens until I stick a rod or something in there to turn the non-driven roller a little bit and get it going again, or empty out the hopper and fill it to ~half full.

it almost sounds like the play at the ends of the roller might be excessive allowing grain to get wedged between the sidewall and the roller. you should have some play in this to adjust if you loosen the housing screws and push the ends together while tightening this back up. also be sure you dont have the two adjustment cams 180 degrees out of phase since your describing the exact same behavior my CK mill gave me when this was the case with my mill. the roller was slightly cocked and bits of grain would randomly wedge between the roller and side causing the roller to stop and need to be broken free.

 

[DVCNick]

Thanks... I don't have it in front of me, but I've confirmed every couple batches it is tight on an .035" feeler gauge all the way across the gap, and there is no obvious "play" that I'm aware of. Individual grains probably can squeeze to the sides of the rollers though.

 

[bracconiere]

i looked closer at the pic in the OP...my mill has little things that funnel the malt to the center of the rollers...like only 1.5", maybe, opening in the middle....