Monster Mill MM-3 - Speed

[jawilson20]

I recently acquired a MM-3 and am digging buying grain in bulk and the increased efficiency. I am currently powering it with a drill that is rated to run at 800 RPM. As I have read tips by others and the manufacturer, I have attempted to run the drill as slowly as possible. When running it slower than full speed, I feel that my trigger finger isn't always consistent and that I may achieve differing crushes from batch to batch. I have only done two batches with the mill thus far so I don't really have enough evidence to conclude just yet.

For those that try to run the drill at less than full speed are you seeing inconsistent efficiencies due to varying speeds of crush? I think that I may attempt running my next batch wide open to see what sort of crush and efficiency I get - and if I am happy with the results I would know that it is something that can be recreated.

 

[IslandLizard]

800 rpm is damn fast for a mill. I try to "gauge it" by the sound to keep it around 150-200 rpm. Doesn't your drill have a preset or speed-limiter adjustment wheel on the trigger? You could measure grain flow too as an indication of speed. Or measure the current the drill draws under load.

Solution: We need a tachometer for our mills!

 

[LovesIPA]

What are the concerns with running the drill at full speed?

 

[jawilson20]

What are the concerns with running the drill at full speed?

Reportedly it doesn't crush as well. From what I have heard is it tends to pulverize the husk more and results in more flour.

 

[jawilson20]

800 rpm is damn fast for a mill. I try to "gauge it" by the sound to keep it around 150-200 rpm. Doesn't your drill have a preset or speed-limiter adjustment wheel on the trigger? You could measure grain flow too as an indication of speed. Or measure the current the drill draws under load.

Solution: We need a tachometer for our mills!

My drill has no speed control or referencing whatsoever. What is the currently preferred low speed Harbor Freight drill out there? My main objective is getting something that will allow for me to consistently repeat the process, so either full speed with my current drill or another drill that will always spin at the lower speed.

 

[IslandLizard]

My drill has no speed control or referencing whatsoever. What is the currently preferred low speed Harbor Freight drill out there? My main objective is getting something that will allow for me to consistently repeat the process, so either full speed with my current drill or another drill that will always spin at the lower speed.

I have this one: Harborfreight: 1-2-half-inch-heavy-duty-spade-handle-drill-93632. There are at least 2 threads here where people love to use that beast for milling.

==> Make sure you get the model WITH the speed control wheel in the trigger. There are very similar looking models that don't have it and they're on the same shelf. 0-550 rpm.

I'm not sure exactly why high speed milling would not be good. Maybe too much shredding or flour? I remember users claiming that between 150 and 200rpm is ideal.

The mills with the large split phase motors have a 10:1 reduction box, and end up around 172.5 rpm on the spindle.

 

[neild5]

The bearings that are used on a grain mill are designed for high radial loads and are not meant to be spun over about 200-250 rpm. Spinning them at 800 rpm will smoke the bearings, score the shaft and damage the frame.