Roller Mills

by Robert Brown (, June 15, 1995

What I want to do is present my experiences regarding mills in hopes that it will help out others. First a quick look at the hobby mills available to us homebrewers. Keep in mind that I have not actually ever seen/used these roller mills so my comments are based on what others have said about them. Many thanks to Douglas O'brien ( for a great many of these addresses. Oh, BTW I have in fact masterminded my own mill :), but more about that later. Here I present my backup plan if building my own was not to be.

Commercially Available Mills

Valley Brewing Equipment
1310 Surrey Ave.,
Ottawa, ON. Canada.
K1V 6S9
Tel: (613) 733-5241
Fax: (613) 731-6476
This local (same province) mill is relatively new and I have received favourable reviews (2 total) against other mills. Adjustable, 2 roller design with good throughput and crush. $145 Can ($99 US) +shipping.

Jack Schmidling Enterprises
18016 Church Rd
Marengo Illinois 60152
Ph# 815-923-0031
fAX# 815-923-0032
Adjustable or fixed rollers, good throughput/grind. Concerns about the unequal adjustment of the rollers. The most expensive but viewed very favourably by most.

Glatt Manufacturing
P.O. Box 116
5 Port Way
Dayton, WA USA 99328
tel: 509-382-4356
Adjustable 2 roller mill. Considered a good mill. Concern about the plastic gears but not a serious problem. Most mills have a follower roller but this one drives both rollers.

Brewers Resource
409 Calle San Pablo #104
Camarillo, CA 93012
Ph# 1-800-827-3983
A new 2 roller adjustable mill that I have not received independent comments on. Brewtek claims comparable/favourable results when compared to other rollers. $90 US+.

Listerman Manufacturing Company
1776 Mentor Ave.
Norwood, OH USA 45212
tel: 513-731-1130
Adjustable 1 roller/plate mill. Concern about the single roller have been voiced. $75-$80 US+ makes it the least expensive roller.

Corona Mill
Columbia, South America
A very common (not a roller) and inexpensive ($40-$50 Can) mill on the market. Quality and quantity of grind is a concern. I have actually seen one of these, believe it or not.:)

No connection blah, blah, blah. If I had bought one it probably would have been the valley roller mill. Cost, quality, US exchange, local product, etc etc. check them out yourself.

Other Roller mill designs:

Home roller mill makers have been known to happen. Some were nice enough to feed my thirst for knowledge, here in short are there designs.

Terence Tegner(
Yep, this is the guy from Africa. Terence engineered a 2 roller mill that will handle 10kg/min. Obviously motor driven it has 2 unknurled 6" diam X 10" length rollers made of mild steel. It spins one roller at 350rpm while using a different sized pulley (driven by the back of the same round pulley belt) to give the second roller a slightly diferent speed. This rolls/turns the grain as it is being crushed.

Andrew Keegan (
Forwarded me 2 roller designs but omitted his own as "experimental". Either a great loss of ideas or a plot of some kind, I'm not sure which.:) They are(in short):

Chris "Barny" Barnhart's (
Made a roller with 2" diamond knurled rollers. He feels that around the 4"-8" mark a smooth or only roughened roller is necessary. This seems reasonable to me and of important design consideration.

Tom Clifton
Made a roller mill of hard maple that were 4" in diameter with axial grooves to provide grip. He also noted a give in his bearings when crushing and would consider simple brass bushings considering the infrequency and low rpm's of use.

Will Self(
Forwarded me a design for a non-centered roller mill. This design used 4" diam, 40 schedule PVC tubing held in place by furniture casters fastened to the frame. A simple hand crank and cog(screw head + hole) system was used to drive both rollers. Knurling was applied with a Knife and a quality grind was the end product.

Wellington County Brewery(Guelph, Ont. Can)
Obviously not a homebrewer(Micro) but the only other mill I have Knowledge of(and have actually seen). This agricultural mill is best described as 2 wagon wheels which run against each other. Good crush, Good beer the final product tells me this design works.


There are numerous considerations but some very simple/basic ones. A mill must draw grain (sufficiently fast/throughput) between 2 "plates" which will crack the contents while leaving the husk as intact as possible. Beyond these points you should not be constrained by the designs of agricultural/commercial/hobby mills as available materials will be the most limiting factor in producing a functional mill. Those with access to a full blown fabricating shop should consider themselves lucky and in the minority.


Wait to finalize your Plan until you have the rollers in hand. A plan is easy to change but try and find the rollers to fit your plan!

In a proven production situation a fixed roller design is possible but at home adjustment will be needed. Knowing the exact gap needed (?very small) and being able to attain it along the length of a fixed roller anywhere but at a precision shop is dubious. As well type, seasonal, varietal, etc grain differences would best be handled by an adjustable mill. A simple threaded rod/screw adjuster, attached to the follower roller, would suffice in most cases.
Frame/hopper design must be sturdy, reliable and functional. They are essential but secondary to the "rollers" which are the "guts" of the machine. The frame must hold the rollers solidly and incorporate an adjusting mechanism. Such as a simple threaded rod/screw mechanism that moves the roller shaft/bearing housing along a slot or channel of some sort.
The materials mentioned above could all be used however availability, hardness, durability, ease of fabrication, and maintenance required (e.g. rusting) should all be considered.

The shape of the "roller" need not be an actual roller. Wheel shaped "rollers" and a non-centered design could also be considered. In addition larger diameter rollers(4"-6"?) do not need the same/any texturing. The relatively flat crushing "profile" can draw the grain without Knurling. This is important when looking for a roller if you don't have access to the proper equipment for the texturing job.

Fabricating a roller will only work if you or someone you know has access to the right tools and the skills to use them. Having a shop make a pair of first run rollers is as or more expensive than buying a hobby mill. You can look around for the "Homebrew loving fabricating shop owner" and trade some brew for the work. But unless he's your buddy or brother-in-law it's his business and livelihood($$$). A roller made by hand will not do, it must be turned on a lathe (wood or metal) to insure that it will be perfectly true.

Premade rolllers are available from conveyor belt companies and the like but are still a specialty item when new ($$$). Used ones can be found at scrap yards, old factories, used junk dealers etc. You will most often find small diameter, thin walled, and rusted rollers that aren't suitable. However if you look hard enough you might come across a drive roller(s) from a conveyor belt, Printer rollers(toxic inks?), or the oat rollers from an old agricultural mill. Look for textured or large diameter rollers that will not need further modificatio and spin true.

A fixed shaft roller with bearings or bushings is simple to attach a crank handle to. But if both your your rollers are the spin around the shaft type a means of driving at least 1 is needed. I suggest welding or bolting a cog/pulley around the shaft directly on the end plate of the roller. You can then drive it with a chain or pulley belt that runs in between the frame and roller, to either a hand crank or motor. This allows the roller to still spin on it's internal bearings smoothly and precisely.

Wheels, consider the "wheeler" mill. Large diameter (6"+)(No Knurling)and smaller length (2.5"-3"+) may be more easily found either used(cheap) or new($$$). Old agricultural or Industrial material handling equipment (carts/fork trucks) have solid broad/flat faced tires. Caster centers and farm supply shops etc will have suitable($$$) new ones. You can remove the rubber/plastic coating (if any) and check that it has a flat/true surface. These will probably be mild steel and will need to be coated or regularly maintained to remove the rust.

A wheels cracking length is smaller, but the larger diameter will make up the surface area difference with every revolution/turn of the crank. Two shaped grain guards will hold the grain in place. A much thinner frame with a standard adjusting mechanism, hopper and crank handle should be relatively easy to fabricate once you've found your "wheelers".

Non-centered design (similar to Will Self's) may also be a consideration. The main requirement here is to maintain a constant gap for the grain to be drawn through.

Tubing or solid stock with a constant diam could be held or jockeyed" in place with casters/wheels held on a surrounding framework. One side of the frame can be hinged for adjustment and a crank handle and simple gearing system will drive the rollers.

Alternatively thin "C shaped buschings" could be cut to the diameter of the tubing. The "C's" would face each other to create a suitable grinding surface. One side would be adjustable(hinged or sliding) the other crank driven with a gearing/o-ring system for drive transfer. The materials used would have to be smooth to allow rotation without to much resistance. I have a pair of 1" diam X 3" knurled barbell handles with grooves appropriate for a "C bearing". This mini-roller was very close to becoming a reality.

Tubing with a constant wall thickness (even oval or egg shaped profiles would do) of suitably large diameter can be used. By inserting small wheels or rollers in the tubing the grinding surface of the tube can be held from the inside at the desired position. This would be essentially an oddly centered roller that would require a somewhat trickier drive mechanism.

The off-centered rollers are a round about way of construction no doubt. But the materials (common tubing/wheels/casters/etc) are inexpensive (even new) and found at any hardware/handyman store. Will's design works (plans available) and I believe the other off-center designs could work as well. It would just take some work and ingenuity.


After long searching and planning I found a conveyor belt with 2 suitable rollers ($10, nice guys, good deal). The drive roller is 4" diameter knurled aluminum with shaft and bearings in good condition. The follower is a 2" diameter smooth SS roller with square bearing housings. They are both 18" long but the knurled roller is very subtly tapered from the center (like "<4" diam>" but only a few fractions from center to ends). This gives me 1 of 2-8" useable "planes" as a grinding surface (the SS roller is true).

I (with some invaluable help, Thanks Wayne) cut down the original frame and remounted the Knurled roller thusly, [roller], the frame has a "squared C profile". Pieces of angle iron were mounted midway in the frame to form a 3-sided adjusting track along the upper edge of the "C" shaped frame. The 2 rollers now sit at the same height. I/we tapped a threaded rod into the bearing housing, put plates on the adjustable/small roller end, and bolts on the rods on eitherside of these plates. The mills small roller is adjustable and can be slightly angled to be parallel with 1/2 of the Knurled roller, creating an 8" grinding surface. A simple handle was fashioned and the test grind worked:). Later I built a simple hopper out of spare materials at home.

The mill works very well, good adjustable crush and fast throughput. Approximetely 15 turns of the handle for 1 pound (15rev./lb). Even on a lazy day a 5 gallon batch should take only 2-3 minutes of grinding at the most. It's almost a shame, I spent so many hours searching and planning, and I will probably only use it an hour or so every year. But then making the toys is almost half the fun, it is a hobby after all the hours spent are hours enjoyed.:)

Sorry about the bandwidth, atleast none of the dreaded never ending threads were brought up.:) I just hope that more than a quick description of my final design will generate more ideas. Ideally, I would like the HBD collective to come up with the elusive "home roller" design. a reliable mill that can be reasonably made at home.

Apologies for any innacuracies, vagueness, bad grammar, etc etc. Any questions, comments, or rude remarks can be directed to me or posted, I will reply in turn from my thermally protected lurking chamber.

Robert Brown, June 15, 1995