My homebrew shop had one of the Crankenstein 3 roller mills and had nothing but problems with it. When you think about it, getting one idler roller going is no problem. But introducing another idler roller makes the job of getting all the parts turning tougher since the second idler roller has to rely on the friction and interference of crushed grain to get it going. That could be a tough prospect.
I love the simplicity of the MM2-2. It has worked very well for me. I actually bought mine before they switched to the new adjustment knobs and the gap setting was not very stable. I did buy and install the new knobs and the mill is now rock solid.
By the way, conditioning your grain with a light water spray about 15 minutes before crushing is an amazingly good technique. My mill is set at 0.035" and produces a decent amount of flour. But the husks come out almost intact! The bed filters and flows very effectively. I mist and mix the malt in a big tray. Do be careful in how much water you add since too much water will cause that wet flour to cake onto the rollers and you definitely won't be happy. It takes a lot of work to clean that caked on flour off the rollers. So the secret I use in gauging how much water to mist on the grain is to keep misting and mixing the grain until you just notice that the grain doesn't raise any dust when you mix it. That is wet enough. The grain will still seem to be dry, but the husks will have absorbed enough water to make them more pliable and capable of withstanding that trip between the nibs.
Enjoy!
