Dirt cheap, motorized, miniature, roller mill

[alphaomega]

Some background first. I've built a motorized monster mill. That sucker milled malt like nobodies business. Once I finished it, I realized that I didn't very much care for it. I vented about in this thread, looking for a solution that fitted my needs better.

The short story is, I don't need a mill that goes through 10lbs of grain in 0.3 seconds. And I don't want a mill that takes up better part of a room.
I do want a compact mill, that is easy to carry (I want to mill indoors, and take it outdoors for cleaning), that has a small footprint, that is motorized and 'hands off' and of course provides a decent crush. Cheap is nice, but I'm not really on a budget.

I was leaning towards the MattMill Kompakt (sorry, in german, but the pics are self explanatory), and then found the MattMill Student. The MattMill Student was very appealing to me, but there is just not (IMHO) enough price difference between the full on proper mill Kompakt, and the Student (which has a plastic housing and is non adjustable). I've got no problem with the plastic body or fixed gap, but it just seemed too expensive.

Sorry for the rant, now the good stuff.
So I was looking around eBay, to see if I found something 'usable'. Preferably, knurled, to build a mill from, as I don't have access to tools to do much metal machining.
And I found what you use to make the knurls with in the first place. Knurling tool rollers.

So I ordered some, win or lose. And some 8mm rod for shafts. And some bronze bearings.

I did not know how I should attach the knurling heads to the shaft. Maybe metal epoxy (JB weld)? My torch does not provide enough heat to braze.
But, I have successfully soldered stainless before, using a special flux, so I gave it a try and it was a winner!

Then I got some 6mm acrylic (AKA Plexiglass) and drilled holes, aiming for a gap of about 1mm between the rollers. Knocking in the bronze bearings and using my trusted cordless drill, gave it a try...

..and failed. The rollers are only 28mm in diameter (or about 1 1/8") and just wouldn't 'pull' the grain in. Dammit. I really liked the knurling rollers. Small, cheap and hardened! And they soldered sooo good.

Then I thought, before I scrap this idea, I'll try driving both rollers.


Tadaaaa! Some success!

Close up of the soldered rollers and acrylic.

The crush. Maybe floury, maybe some torn husks, what do I know, I ain't got no Ph.D. in malt milling sciences, the point is: First try (or maybe second...), and it at least works.

The rollers were about 6 bucks for the pair. The rod (shaft) I don't know really but in the same neighbourhood. The bronze bushings about 3 bucks. And the acrylic I got in a local shop for about 10 bucks. So all in all, about 25 bucks for the build so far.
(Well, not really true, I spent more buying stuff on the off-chance I'd need it, since the shipping time from China is so long).

Next up, I'll try to motorize it on the cheap (I already got a motor off eBay, but need more parts to come in). Hopefully, I can build a mill that will suit my needs

 

[bionut]

Great, now you can send the old mill to me so you can make more room in the workshop

 

[Citizen86]

While I understand not requiring 10lbs of grain milled in 0.3 seconds, how long does it take for you to do 10lbs with that?

 

[alphaomega]

@bionut: sorry man, I wouldn't even have started it if I hadn't gotten the previous (I wouldn't say old) mill sold locally

 

[alphaomega]

While I understand not requiring 10lbs of grain milled in 0.3 seconds, how long does it take for you to do 10lbs with that?

Obviously, this is just proof of concept this far. It needs a hopper and a gear motor.
But speed is not my concern. If it just does its own thing, I don't mind it chugging along for hours if that's what it takes.
Brewing takes me around 6 hours (give or take). Before that, I make a starter a few days ahead. I'm in no rush at all.

 

[mattd2]

...The bronze bushings about 3 bucks. And the acrylic I got in a local shop for about 10 bucks. So all in all, about 25 bucks for the build so far.
(Well, not really true, I spent more buying stuff on the off-chance I'd need it, since the shipping time from China is so long)...

Any chance you can post up the sources for the cheap bronze bushings and motor - I'm in the same boat as you regarding getting things imported, something that is cheap in the US can become cost prohibited due to shipping costs!

 

[alphaomega]

Hi @mattd2 and thanks for your reply and interest!

I'm currently testing a few things out and tweaking stuff, but mainly waiting for a few key parts to arrive.
I don't really want to post any pictures and stuff right now, as it is not really functioning at the moment (need drive for second roller sorted out). But I will update as soon as I can, hopefully with a video of a working prototype.

Almost all the items are sourced from eBay and I can include 'keywords' and specifications for searching for them.

Again, thanks for your interest!

Edit: Oh yeah, the bushings are 8mm ID x 10mm OD x 10mm bronze bushings sold in a 10 pack you should find it easily on eBay. The motor, search for 'square high torque 24v gear motor' and you'll find the type I'm using.

 

[mattd2]

Hi @mattd2 and thanks for your reply and interest!

I'm currently testing a few things out and tweaking stuff, but mainly waiting for a few key parts to arrive.
I don't really want to post any pictures and stuff right now, as it is not really functioning at the moment (need drive for second roller sorted out). But I will update as soon as I can, hopefully with a video of a working prototype.

Almost all the items are sourced from eBay and I can include 'keywords' and specifications for searching for them.

Again, thanks for your interest!

Edit: Oh yeah, the bushings are 8mm ID x 10mm OD x 10mm bronze bushings sold in a 10 pack you should find it easily on eBay. The motor, search for 'square high torque 24v gear motor' and you'll find the type I'm using.

Cheers

 

[kh54s10]

So that thing. while only about an inch wide has 2 drills attached on opposite sides and no hopper yet. How is this saving any space. Not to mention that it will take a lot more time to mill your grains......

Sorry but I don't see any gain here.

Nice project though! :rockin:


My mill while not portable is a Corona, mounted on my work bench. It has a drill motor on one side. I drilled a hole in the bench top and the grains go through the hole to a bucket below.

Space taken about the same as 2 1/2 five gallon buckets stacked. And as far as cleaning, it never has been cleaned. It there is anything dirty it will end up going through the boil so that does not concern me.

 

[alphaomega]

Sorry but I don't see any gain here.

You're not looking. As I said, next up is motorizing it with a cheap dc gear motor. If it works out, then it will be a complete 'hands-off' motorized roller mill that will fit in the palm of your hand.

The gains will be
- Cheap and easy to build and with spare parts abundant on ebay
- Hands off, motorized operation
- Compact and lightweight
- Hardened steel rollers

I'm still waiting for parts. It might make more sense (to you) once the next prototype is done. This is a work in progress, and there will probably be more iterations after the next prototype.

If you still don't see any gain, then fine. It is my project, I build it to fit my needs.

 

[kh54s10]

Sorry, missed the compact motorized part coming.....

It will be interesting to see if it will be strong enough for repeated use.

 

[alphaomega]

Finally the last needed parts arrived.

I'll just post a vid here for now. Still work in progress, but pretty much 'there', just some tweaks left to do. (Sorry for the vid being sidways. The gyro in the tablet is borked.)



I have put two knurling rollers on each shaft now. Had trouble with grain not feeding with just one (too narrow opening). I use gears to drive the second shaft. Unfortunately, the best gears I could find still makes a too big gap (2mm), so this gives a course grind. I tried using the O-ring method, and that worked as well (with ~1.5mm gap).

 

[JohnSand]

I like it. It's a cool gadget. But I think my corona mill is faster (hand cranking).

 

[kh54s10]

While interesting, with the motor on the side it doesn't seem to take up significantly less space than any ordinary roller mill or my corona mill, especially if I take the drill off the drive shaft when not in use. I was expecting something much more compact for the motor from your previous posts.

 

[Stillraining]

I'll go for the 10 lbs in .3 seconds option myself. I have better things to listen too.
Carry on

 

[alphaomega]

I like it. It's a cool gadget. But I think my corona mill is faster (hand cranking).

It probably is. But you'd still need to be *there*, cranking it. That said, I like the corona mill.

While interesting, with the motor on the side it doesn't seem to take up significantly less space than any ordinary roller mill or my corona mill, especially if I take the drill off the drive shaft when not in use. I was expecting something much more compact for the motor from your previous posts.

Well, thanks! Your encouragement really makes me want to share more of my progress on this project. Not.
How about you show me *your* motorized roller mill, built only from off the shelf parts, built with only common tools and that is significantly smaller?
And this is *still* in prototyping stage (even though I'm getting close to being done), but once I'm happy with it. I'm gonna shorten the drive shaft and the threaded rods to correct size and make it as compact as possible. It won't change the size of the motor though.
That will make the dimensions of the entire thing 16x10x6 cm or 6.3x3.9x2.4 in inches (right now it is about 1 inch longer due to the shaft + the protruding rods). The weight is close to 1kg or about 2 pounds.
In what world would that be considered 'big' for a motorized mill? Have you seen the motorized mill thread?

If you hand crank, sure it might not be a lot smaller than just the mill (depending on the mill). But then you'd need to mount the mill to something (usually a base) and you'd need to store that too. With this, I can just place it at the edge of a table with a bucket (or whatever) underneath. Like this:

And you'd need to stand there cranking it...
Same thing goes for using a drill. You either need to stand there or build something to hold the drill and regulate speed.

I'll go for the 10 lbs in .3 seconds option myself. I have better things to listen too.
Carry on

Well, that is personal preference. I'd like that too, but if it means big and heavy (and it does), the small and slow for me. But on a side note, this thing is pretty quiet, which is a nice side effect of being small and slow



Lastly. All of you. If you don't get what I'm aiming for here, fine.
I can handle *constructive* critizism. If you feel the need to post just to say, 'this is slower than x' or 'I prefer y' or just your general disapprovement. Don't. Not helpful.

 

[Sadu]

I make a lot of projects myself. I enjoy the process and recycling stuff that would otherwise go to waste. Sometimes the projects come out great, other times they cost more and don't work as well as a bought one - but there is still the satisfaction that goes with making something.

Maybe everyone here is happy with their grain mills? I'm happy with mine, crank handle isn't a huge problem for me. But I respect the notion of wanting something better and having a go at making it yourself. I also agree that something that can be stored easily is more important than something super-fast, given you can mill the grains in advance and just leave it running.

FWIW I made my own temperature controller and it's not as good as a $1.80 temp controller circuitboard off Aliexpress. This is the way of the world sadly, it rips my nighty how the cost of parts exceeds the cost of a finished product.

Anyway keep it up, make it how you want it and enjoy the process of creating something that you need from scratch.

 

[rekoob]

I like it.
I use a corona mill right now (bucket w/ drill) and would go this route in a second.
Don't get me wrong, the corona mill works GREAT but still takes up some room that I could otherwise use for something else or even better not use at all.
I'm in the process of re-building my garage and trying hard to organize and clean it out at the same time.
I'd say almost half the stuff in my garage is brewing stuff that takes up a lot of room. I have two motorcycles and a motorcycle lift, two tool boxes and it all take room. saving room where I can is a top priority and a smaller mill that can do the job would be a plus.
Standing by for updates.
Well done.

 

[JohnSand]

When you post your method, you should expect others to respond with theirs. That's what happens on a forum, or in conversation. Do what works for you, everybody has their own preference.

 

[alphaomega]

This morning I fabricated another pair of perspex plates and got the gap down to 1.7mm. That is probably as small gap as it gets with the gears I'm using. That still gives a very coarse crush, but I hope that with overnight mashing efficiency won't take too much of a hit.
I already know that friction drive with O-rings works as well, but if I were to use that, then I'd like to locate something better to hold the O-rings. I'm looking at timing belt pulleys. They're cheap and aluminium, so they should be easy to modify.
For now, I think I'm pretty happy with the gear drive.

@Sadu: Yes! I like to tinker as well And yes, most project do end up costing more and/or not working out as well as you imagined. But yeah, the satisfaction you get when you build something that you are happy with is awesome.

Well, it is a good thing if people are happy, right Personally, I think the malt mill market is still behind.
Why is no mill motorized from the start? And motorizing is always an after thought. What I'd like is an appliance. A mill and motor designed to work together (sized properly) and in a nice 'package', that can be stored in a cupboard. A lot of the size when motorizing comes from mounting on a plate, shafts not lining up, excessively long shafts and of course, the motor and mill ending up 'lined up', making the whole thing 'long'. If it was designed an build as a whole, as an appliance it could be sleeker.
I was thinking before about building a mill that attaches to a cheap meat grinder motor (I used one of those for the monster mill I used to have).

Really. Why isn't there a malt mill, that is already motorized and convenient to use and store for homebrewers?

 

[kh54s10]

While interesting, with the motor on the side it doesn't seem to take up significantly less space than any ordinary roller mill or my corona mill, especially if I take the drill off the drive shaft when not in use. I was expecting something much more compact for the motor from your previous posts.

Well, thanks! Your encouragement really makes me want to share more of my progress on this project. Not.

I need to be more tactful or explain better in my responses. Early on I didn't notice that the first design did not have the gear motor that you planned on adding.

So when you posted the new picture I expected it to be a lot more compact. I now see that you still plan to tighten things up. If you can get it smaller great, I was just attempting (yes tactless) to state that it is not much of a space savings yet.

It is a neat project. Keep it up.

 

[Singletrack]

Cool project. Good question about the lack of a mill appliance. I'm committed to hand cranking, because I like a little sweat in my beer, but an appliance would be tempting.


A compact mill is a great goal, but if it doesn't work out, you could go the opposite direction. Make the thing as large and complex as possible, just for fun. I would love to see the grain moving down a small conveyor belt, dropping over a waterfall (grain-fall), ringing a bell, hoisting a flag, flying out of a centrifuge, etc.


Regardless, it will be cool because you built it.

 

[Weezy]

I like it! Great project. Keep it up.

You know what would be fun. Double crush. First set for a coarser first crush, then a second fine crush for BIAB. (Then figure out how to separate the husk in-between)

 

[alphaomega]

I was just attempting (yes tactless) to state that it is not much of a space savings yet.

It is a neat project. Keep it up.

And I'm arguing that compared to other motorized mills, it is considerably smaller.
Thanks though!

Cool project. Good question about the lack of a mill appliance. I'm committed to hand cranking, because I like a little sweat in my beer, but an appliance would be tempting.

A compact mill is a great goal, but if it doesn't work out, you could go the opposite direction. Make the thing as large and complex as possible, just for fun. I would love to see the grain moving down a small conveyor belt, dropping over a waterfall (grain-fall), ringing a bell, hoisting a flag, flying out of a centrifuge, etc.


Regardless, it will be cool because you built it.

Thanks! Yes, I really don't think I'd mind hand cranking either... Hmm.. Ah well, I'm almost done now

Maybe a steam powered mill? Then you could use the hot water to dough in with

 

[Spartan1979]

Well, it is a good thing if people are happy, right Personally, I think the malt mill market is still behind.
Why is no mill motorized from the start? And motorizing is always an after thought. What I'd like is an appliance. A mill and motor designed to work together (sized properly) and in a nice 'package', that can be stored in a cupboard. A lot of the size when motorizing comes from mounting on a plate, shafts not lining up, excessively long shafts and of course, the motor and mill ending up 'lined up', making the whole thing 'long'. If it was designed an build as a whole, as an appliance it could be sleeker.
I was thinking before about building a mill that attaches to a cheap meat grinder motor (I used one of those for the monster mill I used to have).

Really. Why isn't there a malt mill, that is already motorized and convenient to use and store for homebrewers?

Good point!

 

[TasunkaWitko]

It's a Scandinavian thing (and, in my case, a German/Scandinavian thing) - we like to tinker, build our own, save a little money, be self-sufficient and incorporate improvements that fit our needs and our situations. We also like to come up with solutions for whatever issue we are facing at the time.

I say "Bravo, AlphaOmega" - it's a worthy project! But what I'd really like to know is if you have any good, husmanskost-style recipes for kalops, äppelfläsk or gravad älg!

 

[GilaMinumBeer]

Really. Why isn't there a malt mill, that is already motorized and convenient to use and store for homebrewers?

https://www.amazon.com/dp/B00DII1VNG/?tag=skimlinks_replacement-20

 

[alphaomega]

@GilaMinumBeer: Yeah, well that's a grain mill not a malt mill. I'm willing to bet that grinds and not crushes (you can see from the design that it probably has a conical grinding 'wheel').
But still, that, but with with a pair of short rollers instead, is exactly what I mean

 

[GilaMinumBeer]

@GilaMinumBeer: Yeah, well that's a grain mill not a malt mill. I'm willing to bet that grinds and not crushes (you can see from the design that it probably has a conical grinding 'wheel').
But still, that, but with with a pair of short rollers instead, is exactly what I mean

Malt isn't grain? Since when?

It claims it can produce a coarse "crack". I expect a result similar to a corona. Beyond that, MoreBeer does have a pricey 6lb per minute appliance.

 

[alphaomega]

@GilaMinumBeer: Yes, malt is grain. But you know what I mean. Grain mills usually intend to produce flour.
But, it might be usable if it in fact can produce results similar to the Corona (however, I wouldn't buy it based on that assumption, the coarsest setting still may be just flour).
And that is not an 'appliance' you can put in a cupboard I've seen other motorized *commercial* malt mills as well.

I think you know what I'm getting at. Don't tell me there isn't room in the market for a motorized roller mill, that is more like a kitchen appliance?

 

[JohnSand]

I would love to see a kitchen appliance mill that crushes grain.

 

[Stillraining]

Agreed .....but it has to be relatively fast! Or it will not get used or bought by the general consumer IMO.
Few are going to want to listen to a kitchen mixer or blender noise level for more then a minute or two at the most. At least not indoors in your kitchen which the OP is targeting.

In one of his earlier statements he wasn't concerned with speed, that it could run for hours if need be....Id like to see a poll taken to see it that sentiment is held by very many other brewers. I'm going to go out on a limb and say not.

I could buy this and attach it to the wife's Kitchen Aid mixer..but for all of the above listed reasons I would never do it. https://www.amazon.com/dp/B003DVP1V6/?tag=skimlinks_replacement-20

So for lots of us whom can grind 50lbs free at the LHBS in < 10min I would think criteria would have to be in some order as those listed below in order of importance for purchase consideration.

1) Fast
2) Cheap
3) Noise
4) Size

3 and 4 are sort of exchangeable...if its really small and FAST I can put up with the noise. If its slow it better be whisper silent no mater the size. There is a finite limitation to crushing corresponding to roller speed vs roller size..I dont see the OP's first mock up going anywhere market share wise at its current rotation speed. In crease that 10 fold and it might be a good start.

 

[alphaomega]

@Stillraining: Smaller motor an slower crush, means a lot quieter operation. Personally, I prefer a smaller footprint over faster crushing. But I agree, if someone were to market a thing like this (and I really hope someone does!), it would probably need to be reasonably fast. Like I said before, I used an el cheapo meat grinder (800W stall power) to power my 3 roller moster mill before. No problem. And that ate through 10 pounds of grain in a handful of minutes.
It should be perfectly doable to build an 'appliance' mill, that would do 10 pounds in 10-15 minutes. Longer rollers, equal more torque needed. More torque equal more stress and heavier more rugged parts. So, if one is willing to trade 5 minutes for 15, 2 inch rollers would make the mill part a lot less heavy. The gearbox would only need to handle a third of the torque, so it could be smaller and lighter and the motor only needing to put out a third of the power. It's all in sizing the individual components together and fitting it together nicely.

 

[Stillraining]

Agreed. Your on to something for sure. Price point to solve all the restraints will be the bug-a-boo I think.

Carry on.

 

[jddevinn]

Mill
+
https://www.amazon.com/gp/product/B00LTM3AT6/?tag=skimlinks_replacement-20
+
power converter
+
http://www.mcmaster.com/#catalog/122/1224/=13dqgec
+
Bend up a bracket

=

motorized about the size of a 5 gallon bucket

 

[alphaomega]

First I thought you were happy to see... something... But I guess that is your knee
There's something else in front of the mill, no? Platechiller? For extra weight?
That is a pretty darn attractive solution! Kudos!

 

[JohnSand]

This may be a completely different direction. I used a blender for three years to grind grain. It does result in plenty of flour, that doesn't matter with BIAB. It took 10-15 minutes to grind a batch. Which is fine because that's how long the strike water takes to heat. A blender stores easily, partly because of it's big shortcoming: the grain stays in the jar, requiring it to be crushed in small amounts and judged by eye. Your appliance might benefit from a hopper that separates from the grinder, and in which the other parts fit for storage. I'm okay with a modest hopper, my corona hold about two pounds. If the final product is the size of a toaster, and grinds a batch in ten minutes, I think there would be a market for it.

 

[alphaomega]

@JohnSand: I very much like the idea of a hopper that fits the rest of the parts. I'm ok too with a smaller hopper, since you'll have your hands free to top up.

I've talked about the Matt mill before. I really like the size of that thing. Here's a german brewer that used a similar motor to @jddevinn:

I really like that. That is pretty close. What is missing, is that the drive shaft adds about a third of the width and the motor (and mill) is bolted to a base. I'd like to see the motor turned over, so that the entire thing is more 'square' and a way to mount the motor directly to the mill housing and without the long drive shaft. Add a custom hopper that fits over the thing and done! I'd buy that if it was sold as a unit.

 

[jddevinn]

First I thought you were happy to see... something... But I guess that is your knee
There's something else in front of the mill, no? Platechiller? For extra weight?
That is a pretty darn attractive solution! Kudos!

I had a spare electrical project box so I threw the power converter in the box, added a switch that I had laying around as extra and mounted it on the board so that I wouldn't have to pick it up each time I moved the mill.

I stole the idea and motor listing from someone on here... maybe brewindog

@JohnSand: I very much like the idea of a hopper that fits the rest of the parts. I'm ok too with a smaller hopper, since you'll have your hands free to top up.

I've talked about the Matt mill before. I really like the size of that thing. Here's a german brewer that used a similar motor to @jddevinn:

I really like that. That is pretty close. What is missing, is that the drive shaft adds about a third of the width and the motor (and mill) is bolted to a base. I'd like to see the motor turned over, so that the entire thing is more 'square' and a way to mount the motor directly to the mill housing and without the long drive shaft. Add a custom hopper that fits over the thing and done! I'd buy that if it was sold as a unit.

You could find a shorter coupling on McMaster, cut the shaft down. The motor I bought has bolt holes in the face for mounting, you could make a bracket that connects those bolts to the bolts that are holding the plates and rollers together. I like the base plate on mine as it fits directly on top of a bucket, the motor does overhang about 2".... but I could fix that by cutting down the shaft if I felt like it.

 

[alphaomega]

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