help motorizing grain mill

General Homebrew Discussion
1

Want to motorize my grain mill.  Probably overthinking it at this point, but am trying to figure out the best way to do this.

Motor I have is Power Craft Pro cs-103A. It’s a mini bench grinder I’ve had laying around forever and also sells under name TruPower PowerKraft, Neiko.  It’s variable speed to 10,000 RPM 115v with 120w output. Want to run my mill at under 500 rpm.  Is there any easy way to determine the actual RPM it is putting out if I were to direct connect it to my mill so I know I am not running it too fast?  If I were to run it with pulley/sheaves I am racking my brain trying to figure out the right ratio.

I just want to keep it simple!

2

You want to run way under 500, shoot for something between 100 & 200

3

If you search forum you will find our discussion about this.
I think your motor is too fast.
http://www.homebrewersassociation.org/forum/index.php?topic=5314.45

4

Second that…motor at 10,000 rpm…might take flight!

5

Thanks, appreciate the link too.

Motor I have is variable speed, any easy way to determine it’s speed that I could just set it?

Although after reading through the link, I am wondering if this little motor will be up to the task anyway.

6

i use a corless dewalt on low, works great.

7

What mill do you want to motorize?
3 roller needs more power then 2 roller.
For 3 roller mill you need at least 1/2 hp motor.
For 2 rollers you could have smaller motor.

8

+1 on the drill.  I use a 1/2" corded drill and it works like a charm.

9

it’s a barley crusher 2 roller.

Been using a drill and works fine, albeit from the mention of RPM being in the 100-200 range, assuming that is going fast as well. I have always wanted to have something dedicated and finally have the space for a dedicated brewery and can knock this off the wish list then.

10

Geared motor from Surplus store (if they still have it) will work just fine.
Instructions are all in the post I linked earlier.

Good Luck.

11

I also bet a bench grinder motor is too weak. Even with the speed reduced which will increase power - it may spin fast but stop on the first grain of malt because it is not powerful enough.

12

?? My bench grinder has plenty of torque.

13

Well that’s why I said “I bet” - I might loose. The bench grinder I’ve used slows down the moment you touch something to the wheel. Granted - I’m not doing math here.

14

Well, apparently the one I have was ultimately built by POS.  Slowed it down and was able to stop it from spinning by grabbing it lightly with my fingers.  Don’t think it would stack up against the grain.  Found a good deal on a 1/2 hp 1725 rpm motor that I’ll hook up with pulley’s.

Thanks for the help, the links were useful and got me pointed in the right direction.

15

Glad it worked.
Good luck.

16

Mine could rip your arm off at full rpm, but you have a point, they are not all the same.

17

But that is not torque. Bench grinders are not designed to have torque- the stone wheel could become a shattered projectile. I have not encountered a bench grinder you couldn’t keep from turning on with a slight amount of force from your hand. Grain could do the same thing.

18

As mentioned by others, inexpensive corded drills are great for this.  One thing I’ll add is to use a router speed control (or “variable speed controller”) to get the exact RPM needed.

19

+1