Zero Is The New Black

I am building a wind generator and I'm having trouble figuring out how to connect the hub assembly to the permanent magnet motor. My problems have been mainly two-fold - first, getting the hub assembly to stay in place when spinning and second, getting the hub assembly to actually spin the motor instead of slide around it. The hub assembly consists of an aluminum disc with three wind blades bolted to it, 120 degrees apart. Since I am experimenting with two different motors, I have two different motor shafts to accommodate. The first is smooth all around and about 3/4" in diameter. The second is sort of multifaceted around the shaft with lots of hills and valleys, so to speak. Any help would be much appreciated. Thanks.