Just finished our new grain mill. Using a Monster Mill 3 with the stainless rollers and 1/2 drive shaft upgrade. I have the hopper extensions for our large 10 gallon batch grain bills. I’m driving it with a 1/2 hp 1725 RPM 115v motor through a 10:1 Dodge/Reliance Tigear 56/133-10 gearbox directly coupled to the input shaft using a Lovejoy spider coupling all purchased on ebay. Fabricated a nice handled cover to keep crud out when not in use.
The bucket shelf has a guide to center the Homer Bucket under the bottom of the mill. I used some H bracket brushes that I picked up from Grainger to guide the milled grain into the bucket. The frame is fabricated from TIG welded 1" square tubing. The upper shelf is 3/16 carbon steel and the bucket shelf is 11ga CS.
Wasn’t really sure if 172.5 RPM was going to be enough but we are very pleased with how quickly the mill can crack open our grain mix. Plenty of power to fill the hopper and flick on the switch without a whimper.
Maybe a stupid question but I am not too familiar with electric motors and gear reduction (awesome idea by the way). What if the motor is a 1hp with 3450rpms. I notice that the gearbox stats imput of 1750rpms, would I hurt one or the other with the higher motor attached?
Yes, all gearboxes are designed for a certain load max at a certain RPM… including the lubricant used in the box. Since you aren’t actually going to need 1 hp the horsepower rating would only be a problem if you were to load the gearbox to the point that more than the gearbox’s rated HP was required to do the work. But the RPM (doubled) would be an issue. The worm gear design and even the lubricant used is based on not only load but speed. Doubling the input speed would very likely overheat the gearbox. That would also wear out the mill bushings much faster. Besides, you don’t need that many RPM to mill your grain… we are very pleased with the 172.5 RPM our mill is running at. It mills the grain more than fast enough without producing a dust storm. Like any piece of equipment… running it as slow as possible while still getting the job done is the best practice for equipment longevity.
