You guys are putting loctite on the motor screws? I wouldn't even take the chance of any of that stuff getting inside of my motor.

I use the small 3mm lock washers and my motor hasn't slipped yet. That's the thing with these 6061 mounts. You have to watch not to tighten down too much so as not to deform the mount. I found this out with my 8ight mount. My homemade mounts were 7075 and allowed the use of the full size 3mm washers and I could really crank down on those.