I would just like to add, for anyone thinking of this...If you read the User Guide, this is clearly not designed for large grain bills. A few pounds of specialty grains for the extract brewer and this might be a good idea, but much more than that, even with all metal gearing and your mixer will likely break down. Crisis averted.
"BARLEY — For best results, barley should be hulled before grinding."
"NOTE: Do not grind more than 10 cups of flour at one time; damage to mixer may result. After grinding 10 cups of flour, allow the mixer to cool at least 45 minutes before using it again."