What RPM do you run your grain mill at?

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Seabee John

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I just was gifted a 5 HP 3450 RPM motor. I've got a 2" Drive Pulley connected to a 8" Driven pully on a mandrel, which I'll attach to the barley crusher via coupling. The resulting rpm is 862.5 or a .25 reduction

How fast is too fast? I was hoping to keep with the 8", but if I need to, I'll start looking for a 10 or 12"
 
850 is a bit fast. Shoot for under 500 rpms.

I crush with a monster mill hooked up to an ancient 500 rpm drill. Crush was acceptable at full speed, its even better with the drill hooked up to a variac (reduces voltage) set to 35%.
 
The barley crusher site say's at 500 rpm it yields 6lbs per minute. I wouldn't go any faster than that.


_
 
I used a 1725 RPM dryer motor with my MaltMill. With a 10" sheave on the mill and a 1.5" sheave on the motor, I got the RPM's down to approx 190, and it runs great with a good crush. I would try to keep your RPMs below 300 to avoid pulverizing the grain.



Here is a good calculator to determine resulting RPMs:

http://www.csgnetwork.com/pulleybeltcalc.html

Good luck!
 
Last edited by a moderator:
I affixed an old belt driven variable speed drill press to run my malt mill. I found running 500 - 600 rpm sufficient. I have run it up to 1700rpm and the quality of the crush was the same the only fear I have is prematurely ruining the bronze bushings.
 
Thanks for all the input. It looks as though I'll have to switch up to the 12 inch pulley in order to get it where it needs to be.
 
I found a 12" on amazon for 27 bucks... it's the largest I could find with a 5/8" shaft arbor. According to the calculator that should get me down to 578 RPM. That's a little more than I was hoping for, but I think it will do. The only down side I can think of at that RPM would be shredding husks... anything I'm missing?
 
My mill runs less than 100 RPM and is equipped with a Bodine gear motor.
I paid $5.00 for the motor and $12.00 for the missing cap.
The previous owner had no idea the motor required a cap.


Cheers,
ClaudiusB
 
I run my Valley mill @177rpm and works great.
my MM MD3 roller mill is @230rpm and I found that at high speeds sometimes the grain will not feed into the rollers like the rollers are spinning to fast and the grain does not get grabbed by the teeth of the rollers.
I would try to get it as low as you can under 300rpm
 
I run my BC at 150rpm - Grain is perfect at that speed, but a tad slow. I run a small homebrew store and 50lb grain bills are not uncommon for customers.

Optimally I would like to run it at about 200rpm but no faster, to keep crush quality top notch.
 
So, it's turned out to be more of a monster than I intended, but in the end it's all good. I'll post pics as soon as I get back.

Here's what I got:

3450 RPM 5 HP motor with a 2" pulley

Mandrel with a 4" to 2" step Pulley

Mandrel with an 8" pulley and a coupling to drive the grain mill.

First belt 2" drive (at 3450 rpm) to 4" driven resulting in 1725 RPM

Second Belt 2" drive (at 1725 rpm) to 8" driven resulting in 431.25 RPM operating speed of the mill.

I've yet to run grain through this thing yet, but my guess is that it will work just fine.
 
I used Spider Couplings from mcmaster.com

6408K11 (buy two... one for each shaft)
6408K84 one of these (the spider)
 
My search Fu is strong... Seriously the search engine blows on that site... I typed in "177 rpm gear motor" and "gear motor" Apparently I needed to type in "177.7 rpm gearmotor"

Here is my setup. I used a large project box from radio shack and and on-off-on switch from home depot.

I can try and fund the wiring diagram if you guys have trouble

image-634319132.jpg
 
ok, so I had a little time to start building the cabinet... I've got a good portion done. To follow: cut and install the sides, doors, trim. Finish wiring the switch and cord. Build and install the chute for exiting grain and then finish work. Here are some photos of what I've got done so far.

This is the guts:

IMG00068-20110209-2047.jpg


Top close up of the mandrel crusher connection

IMG00069-20110209-2048.jpg


a better close up of the coupling

IMG00070-20110209-2049.jpg


This last one shows how I didn't modify the crusher base, but punched holes to accept the feet and bolts that protrude from the base. I did it this way because I don't actually own the crusher (Nicksteck does) but still wanted a good tight fit with the cabinet.

IMG00071-20110209-2050.jpg
 
I just got my 177.7 RPM motor from Surplus Center as well. Also, I was pleasantly surprised that the couplers I ordered from McMaster were Love Joy brand. Less than half the price that Amazon wanted.

I used Spider Couplings from mcmaster.com

6408K11 (buy two... one for each shaft)
6408K84 one of these (the spider)
 
1/2 for the motor. 3/8 for the BC. I HAVE NOT tested them yet, but I am almost certain they will work. I will post back tonight as I had planned on doing some brewery build stuff.
 
Just a heads up for you guys, I have a 42R-E bodine motor with almost the same specs as the one you bought, but it's 45 inch pounds of torque instead of 40 and 170 RPM. Here it is: http://www.bodine-electric.com/Asp/ProductModel.asp?Context=8&Name=42R-E%20Series%20Parallel%20Shaft%20AC%20Gearmotor&Model=0680&Sort=11166

I have it hooked up to a monster mill 3 roller mill with the normal sized rollers but SS. It's direct drive with a L90 love joy connector, 1/2" on the MM drive shaft and 3/4 on the motor.

The mill works fine and has enough power for DRY grain, it easily turned 5 lbs of grain into flour the first time I used it (.035 gap).

HOWEVER when I conditioned my grain (wetting it so the husks dont shatter and I get a VERY VERY nice crush with the husks intact) the mill will EASILY bind if I put more than a handful of grain in it at a time. 45 inch pounds of torque just isnt enough in direct drive.

I've ordered (but have not received yet) some ANSI 25 chain sprockets from mcmaster carr that will allow me to double the torque and halve the RPM. (18 tooth for the 3/4 and 36 tooth for the 1/2), ANSI 25 chain is rated for 140 pounds of sheer, so it should be fine sense 90 inch pounds is 8 foot pounds of torque.

Hopefully that will solve my mill binding issue with conditioned grain.
 
Just to expound on the above, 3 roller mills require more torque than 2 roller mills, or so I've heard. I will also test some conditioned grain to see if I run into the same problem with my 2 roller Barley Crusher.
 
Yikes. I would think that 40 in-lb. would have been plenty. Thats almost 500 ft-lbs. We'll see, I've got all the parts. I've got the 2" rollers.
 
What size bore are you all getting on the couplings from McMaster for the 177.7 RPM 115 VAC GEARMOTOR and Barley Crusher?

1/2 for the motor. 3/8 for the BC. I HAVE NOT tested them yet, but I am almost certain they will work. I will post back tonight as I had planned on doing some brewery build stuff.

I checked these tonight. The Barley Crusher is 3/8, but VERY tight. I had to tap on it a bit to get it on. The motor is 1/2 and not nearly so difficult to put on.
 
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