Frequently Asked Questions




How does the 3-roller work? What is the advantage?

The 3-roller mill has several advantages and few disadvantages. It has greater output than a 2-roller model running at the same RPM. It provides less husk damage, which aids in sparging. Also, the 3-roller mill more fully separates the starch from the husk, while providing superior grain feed, even with wheat. The 3-roller mill's only disadvantages are the additional power requirements to drive it, and the tendency for brewhouse efficiency to be higher than initially expected.

The 3-roller works by pre-crushing the grain in the preliminary gap between the top two rollers, then opening the husk to expose the crushed kernel in the secondary gap with the third roller. The top gap is fixed at approximately .060" which easily pulls in both wheat and barley, softening the starch without tearing up the husk. There are gaps on either side of the third roller between it and the top rollers. The one closest to the driven roller is considered the front of the mill, where most of the grain will be discharged during milling.

As the grain is pressed between the two main rollers, it covers the bottom third roller. The drive roller forces the grain out the front gap, separating the starch from the husk. The grain headed for the tighter rear gap merely drops onto the bottom roller, which delivers it to the front gap. While milling, very little grain will be expelled on the rear side of the mill. It is important to plan for this when designing your base/hopper.

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What is the Warranty on a Monster Mill?

Let me start by saying that I'm not a Lawyer. There is no "legalese" in the Monster Mill Warranty. Our Warranty is simple...Your satisfaction is guaranteed or you get your money back. If you buy a mill, and you don't like it, mail it back to us and we will refund your money. If it doesn't perform up to your satisfaction, mail it back to us and get a refund. Basically, we want you to be happy with your mill. The last thing we want is an unsatisfied or disappointed customer. There is nothing more depressing than paying hard earned dollars for something, and feeling bad about it.

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What RPMs should I run my mill at?

The best speed to run all of the drill driven mills at is around 150-250 rpms. Does it have to be exactly 200 rpms? NO WAY. A range of 100-300 is fine, and if you are willing to have a little more flour, then you can run it a little faster. I generally tell folks to run it as slowly as your drill will run it without stalling plus a little more. It usually takes a little more torque to get the mill going than to keep it going, so you will have to give it some more power to start the mill, and then slow it down once you are milling. You should experiment with faster/slower speeds and see what it does to your grain.

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What should I set the gap to on my mill?

The gap on the 2-roller mills should be set somewhere around .037 - .055". You will need to assess the crush, and determine if the gap should be smaller or wider. On the two roller mills you will find a point at which the mill will stop feeding the grain when you close the gap too tightly. You will run the drill, but the gap is too small for the grain to fall into, and the drive roller will just spin and not feed. How you crush your grain is up to you. It is important that you experiment with different settings and find out what works best for you. Generally it is not necessary to change the gap frequently. Most grist will crush just fine using the same gap. Unless you have extremely dry or moist malt, you shouldn't have to adjust frequently.

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How do I measure the gap?

Use a feeler gauge. Its a tool that you can buy at almost any good autoparts store. It is a stack of small pieces of metal in different thicknesses. They are bound together, and marked for thickness. To achieve gaps that are not the same thickness as a single blade, stack multiple blades together to add up to the gap you want to measure. The blades should go into the gap between the rollers with a minimum amount of force, and should not be crushed in the gap. Try to adjust the gap on both ends of the roller to be the same. There is some slack for a tapered gap, but this will put unnecessary stress on the bushings.

On the models with adjustment knobs you can mark an arrow on the knob, and then turn it to set the gap at different points and mark on the frame what the gap is at the corresponding knob position. This way you can repeat different gap settings without even getting out your feeler gauge.

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How can I motorize my mill?

This is a very complicated answer. We recommend you use at least a 1/2 HP motor for our small 1.5" diameter roller mills, and 1 HP for our larger 2" diameter roller mills. Use a capacitor start motor if possible. They have much higher starting torque and should be able to start milling after the hopper is loaded. If you don't have a capacitor start motor, you may just have to have the mill running when you load the hopper. Get the RPMs down as much as possible. To do this you will need to use as slow a motor as you can get, and put a very small pulley on it, and put as large a pulley as possible on the mill. The biggest problem with this approach is that the pulleys end up being very large.

Most AC motors run at the slowest speed of 1725RPMs. This means that you need to reduce the speed by a minimum factor of 10. So you will need a mill pulley that is 10 times the diameter of the pulley on the motor to get down to 172.5 RPMs assuming your motor runs 1725 RPMs. When using pulleys to drive the mill it may be preferable to widen one flat on your mill's drive shaft using a metal file. The flats are designed for drill driving, and will work better with a pulley setscrew if they're wider. This is easily accompished using a metal file with the drive roller held firmly in your bench vice.

Pulleys to complete a motorization project are readily available from several sources including Grainger, and McMaster Carr. Look for a small pulley with a diameter of 1.5" or less, and a large pulley to mount on the mill of at least 10" with 12-14" being preferable. Worth noting is that usually the pulleys will have different pitch diameters depending upon the width of belt you use. If you use a narrower belt, it will ride lower down in the pulley groove, and effectively reduce the diameter of the pulley.

There was a very informative article written in BYO a while back, that has all the specific information you will need to complete your project. We worked directly with the author to provide accurate information. Gear reduction motors are also an option but they are usually out of the price range of most home brewers. If you can find one used for a good price, I have heard of several folks using them sucessfully, but you must make sure you have enough torque to drive the mill, or it will stall while grinding.

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What does the mill come with?

The mill comes just as you see it in the pictures on the web site. Mounting bolts are included, as well as set screws or thumbscrews for the adjustable models. Our mills have Monster Mill engraved into the side of the aluminum frame.

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How can I build a base/hopper?
What is the best way to mount my mill?


The simplest base is just a piece of 1/2" or 3/4" thick high density fiber board at least 8" wide and 18" long with a hole for a funnel over the gap, and four mounting holes for the mill. Make sure to drill the mounting holes oversized (at least 5/16") so that there is clearance to properly align the frames for perfect spinning of the idler rollers.

I personally have found it easiest to mount my mill underneath the base and cantilever it out over the edge of my brew stand at a height that is just above my 5 gallon bucket that I mill into. The mill is mounted at one end of the plywood and the other end is screwed into my brew stand. This way it hangs out so I can place my grist bucket under it and attach the drill.

You can also place the base on top of your grist bucket with the mill underneath and the shaft sticking out of a slot cut into the bucket. You can also top mount the mill and place another piece of fiber board on top of the mill with a hole or slot cut in it for the hopper/funnel.

All of our drill drive mills have threaded mounting holes on the top and bottom of the end frames for whatever mounting configuration you can come up with. We include plans for a simple base and hopper configuration like what I use. The drive shaft can turn clockwise, or counter clockwise, as long as it spins and pulls the grain down into the gap. We always like to hear how people are using their Monster Mill, and if you have a Brewing web page we would like to link to it to show other folks how Monster Mills can be configured.

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Do you sell wholesale to brewshops?

Yes. A Monster Mill at your brew shop can be a great asset to your customers by providing a consistent crush. Please send e-mail to me at ffrancis@monsterbrewinghardware.com and I can send a price list with our terms. We don't drop ship, as we would rather you have a sample of our mill that your customer can see first hand.

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Do you ship Overseas? How much does it cost?

Yes, we are willing to ship mills anywhere in the world that they are needed for folks making homebrew. I have found that the United States Post office provides the least expensive shipping rates for parcels leaving the US. International shipments go via USPS International Priority mail for a flat rate of $45 to anywhere that USPS goes. (Canadian customers pay only $30) Our shopping cart can handle international transactions, all you need to do is use the shopping cart on this web page, and shipping charges will be added correctly, as long as you're ordering only one mill. If you would like to order more than one mill, please send us an e-mail for a shipping quote. Generally we can send as much as one MM-3 and one MM-2 mill or less for one shipping charge of $45. Any 2" mill will have to ship by itself, as well as two MM-3 mills. If you are also purchasing a base/or hopper for your mill, the shipping cost may increse substantially. Please see the order info page for detailed information. If there are any taxes or duties due to your government, you will be responsible for them. Its usually easy to call your local customs office, and inquire about duties for imports to your location.

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