Malt mill build??

[sbushwhacker]

I am getting the materials to build my roller mill and found some nice 2-1/2" aluminum shaft. Most plans I have looked at use steel or stainless? These are also available to use but I like the thought of working aluminum (much easier) to knurl and bore out. My only concern was wear but I am convinced this would be minimum since the two rolls never touch each other. Has anyone used this?

 

[Catt22]

Aluminum is too soft to use for the rollers. The rollers don't touch each other, but malt is rather tough and abrasive. It will wear down the aluminum rollers rather quickly and if they are knurled it will wear them smooth in no time. There's good reason why the factory mills use steel rollers. IMO, you'd be ahead of the game just buying just about any of the commercially available mills. They aren't all that expensive and if you factor in your labor and materials it will be pretty close on cost. I do admire DIYers and I'm a gadget freak myself, but I would suggest buying one of the bare bones basic mills and put your effort into fabricating a hopper, a stand and motorizing it. That should keep you busy enough for awhile. Malt mills necessarily require a fair amount of precision in both the design and the machining due to the close tolerances required to keep the rollers parallel. It is generally preferred to have some means to adjust the gap and that also requires some precsion machine work. Monster sells this one for $104 plus shipping which is a bargain price IMO:

http://www.monsterbrewinghardware.com/mm-2.html

 

[EvilTOJ]

Catt is right, aluminum is just too soft for a grain mill. The knurl will wear off in no time and you'll get all kinds of metal bits in your mash.

 

[The Pol]

Aside from the knurl...

Would the shafts be milled as a part of the roller? Or would they be press fit in the ends? If press fit, I can see the stress of the grain being squeezed between the rollers really wearing on the PF where the shaft comes into the roller with all of that side loading.

All mills that I know of are steel rollers, all of these reason are why.

 

[sbushwhacker]

Well I concur that the aluminum rolls will wear, so I have started making them today from cold roll steel. I have turned the ends down to 3/4" and plan on using roller bearings. Yes it would be so much easier to lay down the cash and buy it, but the material is free and I can use the machine shop at work and besides just think how good it will feel when I finish it. I am sure that I can build a mill with closer tolerances than a MM Mill. thanks for the input, pics to follow soon.

 

[Hang Glider]

Welcome to the forum, looking forward to your pics.
With your skilz and access to a machine shop, the mill is just the 'first' thing....

 

[bendavanza]

Post pics of your mill build. We always appreciate fine craftsmanship.

 

[sbushwhacker]

I don' t believe I can upload pictures at my member level, but this is taking much longer than anticipated. Lesson learned was always make a scale drawing first! I am using roller bearings and had turned mt roller shafts down to accept 3/4" bearings. Found out there was not enough room for roller clearance. Then had to use 1/2" bearings and turn down the shafts further. I am also using springs to load the driven roller, so this bearing is slotted .080" with an adjustment bolt on each side. It is almost done now just have to knurl the rollers and design a SS hopper, which I will draw out 1st

 

[bendavanza]

you can post links to pics, and once you've made a few posts your links will be revealed as pics.

 

[sbushwhacker]

Finished my mill yesterday, took a long time but hopefully worth it. I also fab'd a SS hopper. When I knurled the rolls I only had a fine roller tool, this gave me a smaller pattern (not as deep) and I think this has an effect on my grind. After researching roll gap clearance I came up with .036 as a good number. when I tested my mill I found that .057 gave me a grist that looked about right. Almost ready for 1st AGB.

 

[BrewBeemer]

Well I concur that the aluminum rolls will wear, so I have started making them today from cold roll steel. I have turned the ends down to 3/4" and plan on using roller bearings. Yes it would be so much easier to lay down the cash and buy it, but the material is free and I can use the machine shop at work and besides just think how good it will feel when I finish it. I am sure that I can build a mill with closer tolerances than a MM Mill. thanks for the input, pics to follow soon.

Are you using your rollers end shaft and running it directly on the roller bearings or you using the hardened roller bearings inner race that's matched to that roller bearing shell itself? At the minimum you would need to have the shafts or better yet all the rollers case hardened on their face as a single unit then polished for the roller bearings. You using a roller bearing shell like a alternators roller with a dirt and grease seal built in as grain cracking is a dirty grit mess? As part as having tighter clearances or more precision vs the MM with it's bushings, roller bearings still have a couple thou of clearance even when press fitted and crushed down a little vs broduction manufactured oillite bushing as in the MM. Same clearances when new.
I would use double lipped sealed ball bearings for a lifetime mill with case hardened knurled rollers. Granted I ended up rebuilding my MM3-2 to my specs it was better than having nothing if I sent it back being a mess of a mill that "passed inspection" and was shipped. If I shipped back to Fred at MM I would of had nothing to work with instead I modified the mill to my standards to make it function to my specs. I needed something to start with as I hate machining stainless as an option. Get your 25 posts so you can post your progress and mill photos.
I must agree, bushings suck even oillite bushings vs a sealed ball bearing mill.

 

[sbushwhacker]

It is my intention to post detailed pictures, I have used sealed ball bearings. the rolls were 1 1/2" cold roll steel and I turned down the bearing mating shafts down to 1/2". The stationary roll bearings were press fitted into the frame but the adjustable roller is spring loaded and that bearing frame was slotted to move .080". At this point I have yet to make my 1st AGB but I am not anticipating wearing out these rolls any time soon. If this does happen I will disassemble and turn down the rolls and re-knurl them

 

[sbushwhacker]

Used my malt mill yesterday for my 1st AGB, the grind was a success. The only problem I had was some grain sticking to the roll and shooting out the side of the mill instead of in the bucket. The grist was about perfect and done moments before brewing.

 

[sudbuster]

Used my malt mill yesterday for my 1st AGB, the grind was a success. The only problem I had was some grain sticking to the roll and shooting out the side of the mill instead of in the bucket. The grist was about perfect and done moments before brewing.

Let's see some pics of your mill man! You are using some unusual terminology.

 

[sudbuster]

Aside from the knurl...

Would the shafts be milled as a part of the roller? Or would they be press fit in the ends? If press fit, I can see the stress of the grain being squeezed between the rollers really wearing on the PF where the shaft comes into the roller with all of that side loading.

All mills that I know of are steel rollers, all of these reason are why.

Poll, I was a Journeyman machinist for a subcontractor of Boeing for 17 years, trust me, pressed in bearing stubs will take it .... nuff said

 

[Want2Brew]

Poll, I was a Journeyman machinist for a subcontractor of Boeing for 17 years, trust me, pressed in bearing stubs will take it .... nuff said

How deep should they be pressed in? Would pressing one shaft all the way through the roller be better, worse or about the same as long as the stubs were pressed in deep enough?

 

[sbushwhacker]

The rollers were turned down on a lathe at each end. Each roller is a solid piece. The shafts were turned to 1/2", there is a Idler roller that is not driven and a drive roller that has one end about 3" long and has flats milled into it so a drill motor used to drive it will not slip. the grain being drawn into the gap between the two rolls causes the idler roller to turn. The bearings are a tight slip fit so it can be disassembled. I have pictures but not sure how to post them.

 

[sbushwhacker]

I agree pressed in stubs would be fine I considered building them that way but not sure why I didn't, sure would have saved time though, that was a lot of metal on the floor!

 

[BrewBeemer]

Poll, I was a Journeyman machinist for a subcontractor of Boeing for 17 years, trust me, pressed in bearing stubs will take it .... nuff said

Sorry had to LMFAO on this one, thanks Sudbuster.

No worries about making a chip mess, I milled out 14 pounds of aluminum on my Bridgeport last weekend, ended up with a 2 3/4 pound finished part.
Damn chip pile grew by 8 times the original bar stock in size.
Chips in the carpet get the wifey mad every time. I hear ya, A&P here.
Let the chips fly.

 

[BrewBeemer]

Poll, I was a Journeyman machinist for a subcontractor of Boeing for 17 years, trust me, pressed in bearing stubs will take it .... nuff said

A press fit with the proper ratio of diameter to depth of the pin pressed into the roller will make that pin solid as if machined as a one piece roller with the proper interference fit. Drill rod if running on oilite bushings unless building it as a one piece roller then I would have the rollers with shaft stubs case hardened.

 

[gturner6ppc]

I've been thinking of building a mill, too. My project is a bit odder, though.

At Kroger's I found a 12 quart stainless steel stock pot on sale for $9.09. It's ten inches in diameter. Somewhere around here I've got a piece of 3/4" Thompson rod (case 60) and a pair of 3/4" self-aligning bushings.

So if I make two discs with center holes that can slide into the pot to keep the shaft centered, and if I put spurs on the shaft or drill it and run some rods through it (so it won't spin on the shaft), I should be able to pour the pot full of Quick-Crete, Polyester resin and fiberglass, or other suitable filler material to back the thin wall of the pot. Then I take the saber saw and cut off the top section with the lip and handles and I should have a big roller with a shaft through it (hopefully centered, or I'm out $12 or more!)

If that works out then I spend another $9 and do it again.

If nothing else, I could use it as a heck of a rolling pin as long as I kept the malt betweeen two 18 or 20 gage strips of sheet metal to maintain the proper gap and keep the cement and stainless rolling pin from squashing my little kernals flat.

 

[sudbuster]

The rollers were turned down on a lathe at each end. Each roller is a solid piece. The shafts were turned to 1/2", there is a Idler roller that is not driven and a drive roller that has one end about 3" long and has flats milled into it so a drill motor used to drive it will not slip. the grain being drawn into the gap between the two rolls causes the idler roller to turn. The bearings are a tight slip fit so it can be disassembled. I have pictures but not sure how to post them.

I agree pressed in stubs would be fine I considered building them that way but not sure why I didn't, sure would have saved time though, that was a lot of metal on the floor!

Sorry, gotcha now. Understand why you turned them, faster & easier. Looking forward to pix of your build.

 

[sudbuster]

I've been thinking of building a mill, too. My project is a bit odder, though.

At Kroger's I found a 12 quart stainless steel stock pot on sale for $9.09. It's ten inches in diameter. Somewhere around here I've got a piece of 3/4" Thompson rod (case 60) and a pair of 3/4" self-aligning bushings.

So if I make two discs with center holes that can slide into the pot to keep the shaft centered, and if I put spurs on the shaft or drill it and run some rods through it (so it won't spin on the shaft), I should be able to pour the pot full of Quick-Crete, Polyester resin and fiberglass, or other suitable filler material to back the thin wall of the pot. Then I take the saber saw and cut off the top section with the lip and handles and I should have a big roller with a shaft through it (hopefully centered, or I'm out $12 or more!)

If that works out then I spend another $9 and do it again.

If nothing else, I could use it as a heck of a rolling pin as long as I kept the malt betweeen two 18 or 20 gage strips of sheet metal to maintain the proper gap and keep the cement and stainless rolling pin from squashing my little kernals flat.

Here is a site to check for building a malt mill....

 

[sudbuster]

Sorry had to LMFAO on this one, thanks Sudbuster.

No worries about making a chip mess, I milled out 14 pounds of aluminum on my Bridgeport last weekend, ended up with a 2 3/4 pound finished part.
Damn chip pile grew by 8 times the original bar stock in size.
Chips in the carpet get the wifey mad every time. I hear ya, A&P here.
Let the chips fly.

What the duce were you making? Yeah, chips in the soles have a way of cutting up a wood floor too..

 

[gturner6ppc]

Here is a site to check for building a malt mill....

Yes, I could do something like that (I have full access to a Bridgeport mill and a lathe), but most of the industrial brewing references say an 8" to 10" roll is pretty standard. I have a pair of solid 8" diameter by 2" wide round steel sections, but hobbyists are going to have trouble working with those, so I'm trying to come up with a good mill with big rollers that anyone can make cheaply. So for the past few days I've been thinking on how to accurately run a shaft through the center of the 12-quart cookpot shell, because if I can do it with stuff around the house, instead of popping it into the Bridgeport, then anyone can.

Even if the answer is the rolling pin/steam roller with no central axis, by using varying sheet metal gage rails anyone would be able to rolling pin their grain accurately (with sifting and sorting) and get the same crush as a six-row mill.

This capability alone would be a boon to many who are dependent on Corona mills or beer-store mills that are out of tolerance.

 

[BrewBeemer]

What the duce were you making? Yeah, chips in the soles have a way of cutting up a wood floor too..

Aluminum plate 1 1/2" thick, 5" W x 15" L extension I milled last weekend between my LandRover Disco's intake and trumpet base plate for a longer tuned intake runner length. Dropped the peak 3,100 rpm Tq range by 285 rpm's plus added a spacer increasing the plenum clearance above the trumpets for a straighter cleaner air flow. Engine TQ over and hood clearance limiting factor now. From single to larger 4 hole Bosch disc spray injectors, building a pulser to flush and balance injectors. Cammed chipped 4.6 litre 5 speed street sleeper. I have other intrests. Milled FE intakes for MPI also.

Back to OP; I would case harden your rollers then your set for life with any knurling wear factor. Even a small lathe like my 12" should easily swing up to 12" diameter rollers with reversed jaws plus a backgear for low knurling speed low enough for the diameter surface speed.
With your one piece or going with press fit drill rod it still will be as a solid as a single unit and plenty strong. keep the roller speed lower the better. I'm half way thru my MM3-2, polished the journals then the rollers case hardened. Health reasons have me stopped on more progress, spinal surgery recovery i'm pushing beyond my limits already.

I had a wild idea of two different knurling sizes woth 3 roller gear and chain driven together with a idler sprocket fot chain tension after gap readjustments, I know thinking too much into it for a mill.

 

[BrewBeemer]

Here is a site to check for building a malt mill....

Looks like you also own an old Atlas 12" lathe like I have.

I found on my MM3-2 the wife wanted me to have that the radius on the locking thumb screws that fit the same radius in the eccentrics being stainless and with steel thumb screws it would slip, come loose as well turn out of set clearance when tightening. The hand rounded egg shaped thumb screw ends look like they were rounded by hand on a belt sander on how they were made plus at a larger radius causing the eccentric walking every time when tightening. Instructions stated use pliers to tighten the thumb screws to maintain set adjustment. With steel against stainless it slipped out of adjustment. I install short brass slugs with lathe turned matching the eccentrics radius. With brass against the stainless eccentric and shorter thumb screws they bite better and lock with only hand tightening with no pliers needed. All in the details.

 

[BrewBeemer]

Here is a site to check for building a malt mill....

Nice site thanks for posting. I already have a 1/3 hp with gearbox as a single unit for a direct coupling drive for less bushing side loading vs a pulley belt drive system.
Carl.

 

[sudbuster]

If one wanted to pass by the case hardening of the rollers (to keep it cheap), then these would work for the bearing journals stubbed out the thickness of the bearing plates, and running in scintered bronze. At least in a small mill. Their site is kinda funky.

 

[sbushwhacker]

Finally some pictures posted of my DIY Mill in case anybody is still interested in them.

 

[maxi_beer]

Hi to everyone, im Maxi from Argentina, im building a mill and i have a question, how deep are the knurling in the rollers?. Thanks for your time sorry my inglish. And see you latter.