Found out the reason for the bearings binding on the column mount assembly. The rivets must be squeezed gradually and in sequence. I also reamed the holes for a stress free fit. Once this was done, the rivets spin easily. (Thanks to Marty's RV-12 site from 2009!)
Prepared the stub spar receptacles. As with the rear spar, only polishing was requred for a good fit.
Installed the control column mount assemblies. Used my modified yoke for tight places and was able to squeeze all rivets without major problems.
