I was able to tighten the mount bolts through my happ trackball enough to make it hit an occasional rough spot. I think my routing left a less than perfectly flat plane under the CP, so it twisted the housing when everything was cranked down. I spaced the top of the housing from the bottom of the cp with some rubber washers. then, I used internal toothed lock washers (instead of split ring lock washers) and just snugged up the bolts. holding fine so far.