Need help with motorized mill...

I'm still in the planning stages, so I'd appreciate it if someone can tell me if I have the options right before I decide how to proceed.

I have a blower motor, but my understanding is that the rpm's will be too high for use on a motorized mill. Thus I would need a way to get my rpm's down to less than 300.

Option 1: A pulley system. Seems cheap, but I'm not wild about it due to the danger mangling myself on it.

Option 2: Use a gear box of some kind to reduce the rpm. I saw Sanke Pankey did this and it worked well, but I don't know where/how to find a gearbox.

**Would I still need a capacitor if I used the blower motor?

Option 3: Use THIS MOTOR. It's not free like the motor I have and requires that I buy a capacitor, but won't require any pulleys or gearboxes.

Do I have this correct so far?

Second thing to consider is how to connect the motor to the mill. Most seem to use either a lovejoy coupling, or a spider coupling which they got at Mcmaster.com. I assume you just have to know the dimensions of the mill shaft and the motor shaft to buy this piece. Both seem to work fine, no?

I'd really like to get the gearbox (if someone can show where to buy). I assume I need about a 6:1 gear reduction to get it from 1725 RPM to around 300, no? I'm not sure where I can find such a thing. Most of the gearboxes I find when looking ar 50:1. Is that the top of it's range or is it fixed?

I'm also happy buying the gear motor and capacitor, assuming no pulleys are needed.

So do I have the options correct? What do you guys think?

I went with option 3. I am happy with it and haven't had any issue. I would do it again. I got the motor from surplus center and the capacitor comes with it. The part numbers for the spiderss are below. My mill is a barley crusher. that shaft is 1/2" if you have something different you would need to verify.


Here is my build.
https://www.homebrewtalk.com/f51/finished-my-motorized-mill-186036/


3/8" hub no keyway 6408K133
1/2" hub with keyway 6408K713
Buna Spider 6408K74

I spent months on Ebay looking for a gear motor.

I got one for under $ 100.00

It's a little overkill - 3/8 HP @ 90 rpm and 167 in./lb. torque (you could not stall this thing with an 18" pipe wrench)

I'm using the 3 roller Monster mill.

I sent samples to a professional brewer, and the crush I'm getting is great - my efficiency runs 82-84%

1/4 hp motor should be plenty - my complaint is the rig is really heavy, but it's a super clean rig (see my pics)

Good luck, and you're right about the rpm's - unless you are using an extremely expensive commercial mill, the slower the better.

Brewer3401 said:

I spent months on Ebay looking for a gear motor.

I got one for under $ 100.00

It's a little overkill - 3/8 HP @ 90 rpm and 167 in./lb. torque (you could not stall this thing with an 18" pipe wrench)

I'm using the 3 roller Monster mill.

I sent samples to a professional brewer, and the crush I'm getting is great - my efficiency runs 82-84%

1/4 hp motor should be plenty - my complaint is the rig is really heavy, but it's a super clean rig (see my pics)

Good luck, and you're right about the rpm's - unless you are using an extremely expensive commercial mill, the slower the better.

Click to expand...

IMO, that motor is not overkill at all, it's near perfect for the job. Who cares about the weight anyway? It's not like you will be carrying it around much. the Bodine I am using is rather fat as well, but it sure works well. I'm running at only 115 rpm, but it's plenty fast enough. I think it mills about 2 lbs/minute. Not real fast, but there's almost zero dust and no mess. I typically have lots of things to do while the mill churns away. It operates reliably without having to babysit it at all. Your 90 rpm will be just fine, especially on that MM 3-roller. You should be able to easily double my output and probably more as your rollers are much wider than what I have on my tiny mill.

Forgot to mention, I use a LoveJoy connection - they're great when you don't have perfect alignment.

I think one of my pics shows a rubber hose - that didn't work at all - way too much torque.

rockytoptim said:

I went with option 3. I am happy with it and haven't had any issue. I would do it again. I got the motor from surplus center and the capacitor comes with it. The part numbers for the spiderss are below. My mill is a barley crusher. that shaft is 1/2" if you have something different you would need to verify.


Here is my build.
https://www.homebrewtalk.com/f51/finished-my-motorized-mill-186036/


3/8" hub no keyway 6408K133
1/2" hub with keyway 6408K713
Buna Spider 6408K74

Click to expand...

Quick question. What is the 3/8" hub with no keyway for? I looked at your build. The motor is the same one I bought, I think. Specs say it has a 1/2" shaft with keyway. If the Barley Crusher is also a 1/2" shaft, what is the 3/8" hub without the keyway for?

Did you by chance write that down wrong? Is your Barley Crusher 3/8" with no keyway?

Just want to get my parts right. Thanks again for posting your build. Very helpful. I just ordered my mill. Got an MM3.

Just checked the Barley Crusher site. Shaft for that mill is 3/8." I guess I read your post wrong and you meant the motor's shaft is 1/2."

rockytoptim said:

I went with option 3. I am happy with it and haven't had any issue. I would do it again. I got the motor from surplus center and the capacitor comes with it. The part numbers for the spiderss are below. My mill is a barley crusher. that shaft is 1/2" if you have something different you would need to verify.


Here is my build.
https://www.homebrewtalk.com/f51/finished-my-motorized-mill-186036/


3/8" hub no keyway 6408K133
1/2" hub with keyway 6408K713
Buna Spider 6408K74

Click to expand...

Can anyone help me out? I bought the MM3 with a 1/2" shaft. Spec sheet doesn't mention it having a keyway. I can't seem to find the Mcmaster.com part number for this without a keyway, though. I'm using the part #'s above as a guide.

Looks to me like the 3/8" hub has no keyway, but the 1/2" hub does. Do all 1/2" shafts have a keyway?

Really appreciate it if someone can show me the way. Cheers!

Dgonza9 said:

Can anyone help me out? I bought the MM3 with a 1/2" shaft. Spec sheet doesn't mention it having a keyway. I can't seem to find the Mcmaster.com part number for this without a keyway, though. I'm using the part #'s above as a guide.

Looks to me like the 3/8" hub has no keyway, but the 1/2" hub does. Do all 1/2" shafts have a keyway?

Really appreciate it if someone can show me the way. Cheers!

Click to expand...

From picture on monster mills website it looks like it has a 1/2" shaft with keyway. Just give them a call they will confirm.

Most 1/2" shafts that are used for transmitting torque have a keyway but as with anything there are always exceptions.

I thought the keyway was just a piece of the shaft ground flat.

If you don't have, you can set up your coupler and take out the set screw, then take a drill and make a small indentation where the set screw will go.

You're going to like your mill

Good luck

The MM does have a keyway

Brewer3401 said:

I thought the keyway was just a piece of the shaft ground flat.

If you don't have, you can set up your coupler and take out the set screw, then take a drill and make a small indentation where the set screw will go.

You're going to like your mill

Good luck

Click to expand...

A keyway is a slot milled into a shaft. A coupling, gear or sheave should have a matching keyway. The "key" is typically a short square metal bar which fits into the opening made when the keyway on the shaft if lined up with the keyway on the coupling or whatever is used. The key locks them together and it is usually held in place with a set screw on the coupling, sheave etc. A flat ground on the shaft serves the same purpose, but the key will generally handle much more stress than the set screw bearing on the flat of a shaft.

The MM3 isn't quickly reversible though. The drive shaft is 1/2", but all the other shafts are 3/8". If you want to turn it around (say to switch CW/CCW) you'll have to carefully pop out the bushings and press them back in.

A new gearbox from groschopp is around $150 with shipping and other necessary bits.
https://www.homebrewtalk.com/f51/my-new-mill-station-258609/#post3113579

outside92129 said:

The MM3 isn't quickly reversible though. The drive shaft is 1/2", but all the other shafts are 3/8". If you want to turn it around (say to switch CW/CCW) you'll have to carefully pop out the bushings and press them back in.

A new gearbox from groschopp is around $150 with shipping and other necessary bits.
https://www.homebrewtalk.com/f51/my-new-mill-station-258609/#post3113579

Click to expand...

Can you explain why I'd need to remove bushings to reverse? What difference does it make if the other shafts are 3/8" in this situation? If you reverse the 1/2" shaft, it should turn in the opposite direction, no? Or is it because this has three rollers?

Thanks for the info on the gearbox as well. I went with the gear motor, but it's good to know.

The MM3-2.0 (my mill in the link above) has a 1/2" shaft with no keyway. It does have 3 flat spots milled on the shaft that the setscrew on the lovejoy coupler holds just fine.

Since its a 3 roller mill you'd have to flip the drive rotor to make it run the other direction and still push the grain through the lower 3rd roller.

Also, when I ordered my speed reducer from groschopp (last month) they did tell me that they'd be discontinuing the NEMA housing ones soon. This is the same type of standardized housing the motor had which made assembly a simple bolt it together situation.