Mill motorization

[shoengine]

My friend kicks ass.

A couple years into my brewing journey I picked up a used mill from someone on the forum. Since all it had was an input shaft I used my hand drill to power which worked fairly well.

The downside is of course having to hang out with it holding the trigger. I tried ways of automating, mainly with zip ties but since the mill just sits on the bucket the whole mill will rotate if the powered roller gets stuck, like on a rock, for instance. Had a lot of malt on the floor after that one.

I tried looking at adapting my 1/2 hp Craftsman AC motor but to get the speed down to under 200 RPM would require a 2in sheave on the motor around 20in on the mill, or an assortment of smaller sizes in between, which would require an idler/added complexity. Reducing power on AC motors isn't reliable.

I looked at purpose built motors with transmissions but they were hundreds of dollars new. Amazon has a ton of cheap DC motors though so that seemed like it could work. However most of them didn't seem like they would have the requisite torque at the right speeds. Eventually I gave up and decided to stick with the drill motor.

Eventually my buddy decided to look into this after working with DC motors and controllers that he used when making 3D printed projects. After a few measurements he whipped this up.

Has variable speed, forward and reverse, it is nearly silent until malt is added, and is plenty powerful.

Obviously the unit still sits on a bucket, but I have a plan for that.

 

[IslandLizard]

Excellent, nice build! ^
From the tag on the motor, it runs at 150 rpm (at 24V), which is ideal for 1.5" diameter rollers (~12"/sec linear speed).

Also, that's some seriously sized power supply!

 

[shoengine]

I think the PSU is a little over the top, but he had it spare from an earlier project.The cost of all the parts was $100 (not including the mounting hardware).

 

[OakIslandBrewery]

Very impressive build!

I motorized my mill, first with a variable speed drill then later with a GE gear motor I picked up at a surplus joint. Works great. What I did was build the mill, motor and hopper on to a wood plate so I can mill directly into the mashtun.

 

[shoengine]

Very impressive build!

I motorized my mill, first with a variable speed drill then later with a GE gear motor I picked up at a surplus joint. Works great. What I did was build the mill, motor and hopper on to a wood plate so I can mill directly into the mashtun.

That's great. I was thinking of going that, but wasn't sure that the steam from the hot water would cause issues with the mill.

I was thinking about separately getting a hopper to empty directly into the mash tun but I'd want to rig it with a hydrator.

 

[OakIslandBrewery]

That's great. I was thinking of going that, but wasn't sure that the steam from the hot water would cause issues with the mill.

I was thinking about separately getting a hopper to empty directly into the mash tun but I'd want to rig it with a hydrator.

The mill plate comes off after I'm done milling. It doesn't stay on top during the mash.

That steàm and moisture wouldn't be good for the mill head or the motor.

 

[IslandLizard]

I was thinking about separately getting a hopper to empty directly into the mash tun but I'd want to rig it with a hydrator.

Why not underletting the (milled) grain in the mash tun? Dust free and low oxygen friendly.

I therefore always mill and fill the mash tun outside, in the driveway. I don't want all that grain dust around in the "home brewery" (our kitchen).

 

[shoengine]

Why not underletting the (milled) grain in the mash tun? Dust free and low oxygen friendly.

I therefore always mill and fill the mash tun outside, in the driveway. I don't want all that grain dust around in the "home brewery" (our kitchen).

Full volume BIAB mashes.

I have a plan for the dust. We'll see if it works.

 

[OakIslandBrewery]

Why not underletting the (milled) grain in the mash tun? Dust free and low oxygen friendly.

I therefore always mill and fill the mash tun outside, in the driveway. I don't want all that grain dust around in the "home brewery" (our kitchen).

How would one "underlet" the milled grain into a nash tun? Like a screw conveyor into the bottom of the vessel?

 

[day_trippr]

That would be interesting, but, no, that's not what was meant
Mill the grain into the MLT, then introduce the strike liquor under the grist via the drain port...

Cheers!

 

[sibelman]

he whipped this up.

Wow. Way nicer than the hand drill solution, @shoengine.

Any chance you could provide the make/model of that clamp, and sources for that impressive clamp and Ecetromechanical XD-60GA775 motor?

 

[shoengine]

Wow. Way nicer than the hand drill solution, @shoengine.

Any chance you could provide the make/model of that clamp, and sources for that impressive clamp and Ecetromechanical XD-60GA775 motor?

Sure, I'll check with my friend

 

[OakIslandBrewery]

That would be interesting, but, no, that's not what was meant
Mill the grain into the MLT, then introduce the strike liquor under the grist via the drain port...

Cheers!

OK, I stepped into that one. I thought maybe there was a special technique you guys had under wraps.

I do the underletting of mash water through the bottom manifold/valve in my mash tun. Grain is milled directly in as I mentioned. Very little dust, but I have put to use the big box of covid masks and wear one when milling just in case.

 

[sibelman]

I attached a cloth tube at the bottom/outlet of my mill, long enough to reach the bottom of the receiving bucket (MLT). This contains virtually all the dust. No more coughing or mess.

 

[day_trippr]

I really need to do that to my mill. Right now there's barely a 4" open drop but even that can result in thick malt dust all around the inside of the mill cabinet when the humidity is low. Gotta get 'er done

Cheers!

 

[OakIslandBrewery]

I really need to do that to my mill. Right now there's barely a 4" open drop but even that can result in thick malt dust all around the inside of the mill cabinet when the humidity is low. Gotta get 'er done

View attachment 835352

Cheers!

Go to the home improvement store and pick up a toilet floor flange, screw that to the inside bottom of that cabinet. Then go into your sock drawer and pick out the worst looking, but clean sock. Cut the toe end off and slip it over the toilet flange, maybe put a zip tie to hold it.

If you have small feet, the sock trick might not work. Maybe a neighbor can help.

A shirt sleeve or pant leg could work too.

 

[day_trippr]

Toilet flange or something like it sounds good, sock not so much (too small).
But I have some super old "dad jeans" with one good leg left that will work

Cheers!

 

[shoengine]

I just put a little box under mine so the bucket is right up against the hole.

 

[day_trippr]

That's just crazy enough to work!

Cheers!

 

[OakIslandBrewery]

We're all about good ideas to try to help each other here!

 

[OleBrewing]

those ram mounts are spendy but damn are they well built and worth the money.

 

[shoengine]

Most of the RAM mounts will be going back to him. There just wasn't much room on that little, wood platform so he had to get creative...

Phase 2

 

[Gozie Boy]

Looking to change over from cordless drill to a dedicated motor. Appears DC has more options and is better suited for the job. I know just enough about electrical to be dangerous, so need some guidance to finish this project. For the motor used by the OP, I see it is rated 3 amp at 24v, which I assume uses 72W max (don't know about startup condition). I will need a 110VAC-24VDC power supply and am concerned about the high torque nature of the application esp. start current. What type of PSU would be suitable for such a motor? I do not see any spec sheets, curves, etc for these motors, so a bit of guesswork/over design/experience is needed. Also, I think a variable speed (voltage) control in the PSU would be helpful depending on cost uplift, but not essential if the fixed speed is in the 100 - 200 RPM range. Thx!

 

[shoengine]

Designed and printed a motor housing and spacer for the mill.

 

[sibelman]

Sure, I'll check with my friend

Your mill setup is looking amazing!

Any word on clamp make/model and sources for clamp & motor?

 

[shoengine]

What clamp do you need info on?

 

[day_trippr]

What clamp do you need info on?

I'm gonna go out on a limb and say probably this fancy clamp:

"Pardon The Interruption", but fwiw, my lament expressed here was solved by following the brilliant suggestion provided by @shoengine to prop the bucket up tight to the underside of the cabinet to close that gap

I was prepping for a brew early tomorrow and went ahead and milled the grains tonight - after sticking a 2x4 under the bucket that left barely a 1/4" gap up top. Made a profound difference in the amount of grain dust clinging to the inside of the cabinet - it cut it down to just what was covered at the top by the bucket itself. With the second half of the grind going in a fresh bucket, when the milling was done I tapped the cabinet top a few times, which knocked most of the dust into the bucket before I opened the cabinet. Good stuff!

Cheers!

 

[sibelman]

Yes, the clamp that joins the motor to the board.

 

[mattd2]

@shoengine nice build! I have been wondering about the geared DC motors for a while but not brave enough to jump into it. From the motor manufacturer the rated torque of that 24vdc 150rpm motor is around 6kg.fcm (approx. 5.5 in pounds), however a lot of sources discussing motorising mills with AC motors claim a 45 in pounds is the minimum required to run a mill - how have you found it powering the mill? any problems with it starting the mill? Can you start it with a full hopper or do you need to start the motor first then fill it with grain?
I guess the benefit of the DC motor over AC ones is the torque increases greatly when a load slows the motor down (at least that's what I understand), from some other DC gear motors specs I have seen the stall torque can be 3-4 times larger than the rated torque. Given me some more confindence to try this out for a cheap motorised mill.

 

[shoengine]

@shoengine nice build! I have been wondering about the geared DC motors for a while but not brave enough to jump into it. From the motor manufacturer the rated torque of that 24vdc 150rpm motor is around 6kg.fcm (approx. 5.5 in pounds), however a lot of sources discussing motorising mills with AC motors claim a 45 in pounds is the minimum required to run a mill - how have you found it powering the mill? any problems with it starting the mill? Can you start it with a full hopper or do you need to start the motor first then fill it with grain?
I guess the benefit of the DC motor over AC ones is the torque increases greatly when a load slows the motor down (at least that's what I understand), from some other DC gear motors specs I have seen the stall torque can be 3-4 times larger than the rated torque. Given me some more confindence to try this out for a cheap motorised mill.

I can't speak to the torque requirements. I did mention to my friend that finding a motor that could run slow and put up with the milling was very difficult. I've milled with it twice so far and both times it worked well, with no struggling. I usually start my mill before dumping the grain in, but next time I'll try starting it after filling the hopper.

 

[shoengine]

Your mill setup is looking amazing!

Any word on clamp make/model and sources for clamp & motor?

I'm checking on this...

 

[mattd2]

I can't speak to the torque requirements. I did mention to my friend that finding a motor that could run slow and put up with the milling was very difficult. I've milled with it twice so far and both times it worked well, with no struggling. I usually start my mill before dumping the grain in, but next time I'll try starting it after filling the hopper.

Looks good @shoengine - don't worry about testing it starting with a full hopping for my sake (don't want it getting busted just for my curiosity).

I've found a cheap 24v (or 12v) DC gear motor (although less total rated power than your motor) - total cost including motor bracket power supply and shaft coupler is less that US$35. Issue with using a lower power motor is it will need to be reduced down even further, from the (sketchy) specs it possibly could get by with a rated 135rpm motor, but I might drop that to the 90rpm or even 65rpm version. I've seen elsewhere that at 80rpm it takes about 2minutes per kg of grain to crush (or ~a minute a pound), with the 65rpm version this would be approx 2.5 minutes per kg, or between 10-15minutes to crush a standard 5 gallon batch.

Thanks for the insperation!

 

[sibelman]

Hey, @shoengine , I added a motor based on your listing. It did a fine job with its first run on my most recent IPA. One thing: its quiet whine with no load becomes somewhat piercing when the grain goes in the hopper.

I disassembled, cleaned and lubricated my Schmidling mill, but the unpleasant sound persists. Does this happen with yours?

 

[Deadalus]

Conditioning the grain before milling cuts down very significantly on the dust. I'm also interested in the parts used in the motorization if you you have a chance to put a list together.

 

[sibelman]

Here's some info from my build, @Deadalus I got it all from ebay with total just under $100.

• The 24V power supply I chose is Mean Well RS-150-24 AC/DC Power Supply 150W ebay item 175625043083
• The motor is ebay item 155702171164 (24V 50 RPM): 60GA775 DC 12V/24V 35W High Torque Metal Gear w/ GearBox Motor CW/CCW
• I also bought two couplers -- not sure which I ended up using -- from ebay item 185835199269

 

[shoengine]

I meant post these earlier. I don't have links to them but my buddy bought everything off Amazon.

@sibelman Do you have a video of the whine?

 

[sibelman]

Do you have a video of the whine?

One naked, one with a slapped together enclosure.

 

[Hunky]

Being cheap I first tried (after using a 1/2 drill for awhile) using a spare garage door opener motor.. worked great, until the plastic gear on the drive stripped out. Just needed a better grade gear, which I didn't have. Had forward and reverse of course, as well as a remote if there was a use.

After the gear stripped, I have a friend running our local city rec center and had some treadmills in the backroom for repair/parts. I talked him out of letting me part one.. I grabbed the motor that raises and lowers the treadmill ramp. (forward and reverse and high enough torque). Not the most elegant but works fine. Nice and slow.

 

[sibelman]

After building a crude wooden enclosure, I tested my newly motorized mill, inspired by the experience of @shoengine. It works. It's noisier than I'd like, and the enclosure only helps a little with that, as the motor and gears are acoustically coupled to the mill.

With this 50rpm motor, the pace is about a minute per pound. Certainly no worries about overly high speed.

Time will tell how durable this thing is. I'm still curious about the kind of sound @shoengine's unit makes.

 

[shoengine]

I have a brew slated for next week, so I can check it under load then.