Today I mounted the rudder pedal assemblies. What I thought would be a couple hours turned into an all day job. First, the rudder tubes were too long and had to be fitted to length on both sides, no problem, all fitting blocks are in allignment. This was not hard to do just taking the time to do the alignment. At this point I fitted the end bearings, center bearings and mounted the assemblies in place, now I have some binding on the left side pedals. After a while of looking for the problem, I have found the u channel that the fittings are bolted to on the left side is not in alignment with the rest of the u channels, it is welded lower than the others. Okay, not a real problem a thick washer will bring it up to alignment with the others. All is well until I tightened the bearings to the recommended 30-40 lbs torque and all of the bearings are now binding. In all the years I have been building planes I have not had bearings that are this soft that expand when tightened. Anyway, the rest of the day was spent working on the fit. In the end, all is well but I am courious why this material is being used for bearings, any insight?