Issues with a monster mill

I have a Stainless MM-2 that I bought in April of 2010 that I recently had a problem with.

I've used the mill for 30+ batches without a problem. I have a Black and Decker corded drill driving it.
During this time I've checked the gap and I clean it with a shopvac after every use, but I haven't done anything else in terms of maintenance.

While using it today it stopped milling the grain.
By this I mean that
-the drill continued to spin
-the RPMs went up
-the load went down
-no more grain was passing through the mill.

At first I thought that the drive shaft had become separated from the drive roller, but it was still spinning.
Then I thought that the grain had somehow become clogged above the rollers, but shaking/taping the mill didn't help.

After moving it around a bit, it started working, but then the process repeated itself. Luckily, it started back working again and I finished milling my grain.

My newest thought is that the passive (loose) roller became stuck and that caused the problem. It does rotate freely now, but of course I couldn't check it when the mill was full of grain.

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jldc said:

I sent this email to the Monster Mill customer service people, but I thought I'd see what you guys have to say:

What do you think??

L

Click to expand...

jldc said:

I sent this email to the Monster Mill customer service people, but I thought I'd see what you guys have to say:

What do you think??

Click to expand...

You may just have some gunk in the works that's keeping the idler from spinning freely. If you can take it off the base, and clean off the axles, and wipe the frames clean it should help. I'm pasting in our instructions for binding. It should be a cinch to get the MM-2 going, it's the easiest one to set up, and keep going.

~~fred francis
MBH

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The problem you're having only occurs when one or more of the non driven rollers bind up for some reason. For the mill to feed properly, the non driven rollers must spin completely freely at all times, before, during, and after milling. Grain caught up in the works can cause it, or if the mill is bolted down such that the frames cause the rollers to bind, you can have this issue.

Take the hopper off. Loosen all four mounting bolts. Press the frames together to minimize the end gap. There should not be enough space between the ends of the rollers, and the frames for a barley kernel to fall into. Next, tighten down the drive shaft side frame completely. Next, feel for the center of the freeplay of the other frame, and move it to this centered location. Check all three rollers for spin. They should move freely without any binding whatsoever. You should be able to spin them quickly with your hand, and have them keep spinning. Once the frame is in a place where everything spins freely, tighten it down slowly, checking the spin as you tighten. Tighten a little, and then check the spin. Tighten some more, and check the spin. If the rollers don't spin as freely with everything mounted down tight, as when the mill is just sitting on the base, not bolted down, then something is binding, and you need to locate the issue, and re-align the frames.

It is important to minimize the endplay on the rollers. If you slide the rollers back and forth between the frames, they should move a very small amount, 0.020" or less. The end gap must be smaller than the smallest kernel of barley that you would mill so that no grist gets caught down between the end of the roller, and the frames. When mounting the mill it may be necessary to enlarge slightly the hopper mounting bolt holes in the hopper, or the mounting holes in the base, so that you can press the frames together when the mill is mounted to minimize this endplay.

If you have our hopper, you should be assured of proper feeding. Make sure you have the little triangles mounted in the corners of the hopper. These make a big difference in how things work, so make sure they're installed.

If you don't have our hopper, there are a few key items that you need to address with your hopper design. A slot cut over the top of the mill, with grain falling all over the tops of the rollers will not work well at all. If you look at the photos of our hopper design on the web site, you'll see that there are triangles in the corners of the hopper that keep grain away from the ends of the rollers. This is key because grain caught between the ends of the rollers and the frames will cause binding. Also, you can't see it as well but the hopper extends down below the tops of the frames, and almost touches the rollers. This keeps the grain from bouncing over the tops of the rollers and clogging up the works. It keeps the grain flowing down through the gap. If you've added sides to your mill if top mounted, grain that doesn't go down the gap can get caught between the sides, and the idlers, and stop the idlers from spinning. If you've bottom mounted, grain going over the tops of the rollers can get caught between the idlers and the base. Your hopper needs to extend to almost touch the rollers, to keep grain from flowing over the tops of the rollers, and keep grain away from the ends of the rollers.

Next, how the gap is set can make a difference as well. You need to set the gap to between 0.038", and 0.045" No wider, and no tighter, at least to start. The gap can be set in TWO different knob locations. One, with the gap in between all the rollers maximized, and one with the area minimized. You must set the gap such that the area is MAXimized in the middle of the rollers, and BOTH ends of the roller must be set the same way. To start, loosen the thumbscrews so that the adjustment knobs turn freely. Move both knobs so that the adjustable roller is in the lowest most position, at 6 o'clock. Next, looking at the mill from the drive shaft end, with the drive shaft to the left, (should spin CW to feed properly) you need to turn the adjustment knob in a clockwise direction to adjust the gap. Put the feeler guage in the gap on that end of the roller, and turn the knob CW till it holds the feeler guage in the gap. Now do the same thing on the other end of the roller. Looking at the opposite end of the mill, you need to turn that knob in a CCW direction to set the gap the same way. Put the feeler guage in the gap, and turn the knob till it's tight in the gap. Repeat on the other end, and tighten the thumbscrew, and repeat on the opposite end again, and tighten the thumbscrew. This procedure should set the gap for proper feeding, and give you a good crush that should provide good extraction, and no chance of a stuck sparge.

Speed can play a role as well. You should drive the mill between 100- and 250 rpms. I use a corded Dewalt 1/2" drill, and I run it just fast enough to keep the drill from stalling plus a little more. I always fill the hopper completely to start, and then start the drill, and I don't stop until the hopper is empty. I also run the mill as fast as it will go for the last cup or so of grain so that it cleans everything out of the mill. You should watch the rollers when you do this, and they should continue spinning after the grain goes through, and roll for a bit.

If you work through all of this, and still have problems, then PLEASE let me know, and we can work on determining what the problem is. I'm confident if you look at the mill, and address these issues, then it should feed reliably all the time.

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