Quote from Crankandstein.net in description of their 3D mill, "The third roller is smoother to reduce husk damage. The triangular configuration of the rollers forms two gaps. The first fixed at .070" softens the grain interior and speeds up throughput. The adjustable second gap can then more readily open the husk with less damage and separate it from the starch." I can heartily recommend this mill as I've had one for about 20 years and put thousands of pounds of grain through it with zero problems. I've got mine powered with a very old (70+ years) 1/2" drill with a router speed control.
The old drill and the hopper add kind of a steampunk element. Nice setup.