Have you checked internal dimensions of holes. What I have found is that most parts come out about 0.005 inches oversized external and undersized internal. I believe this is due to the filament squishing out when extruded. It is the natural expansion that allows one strand to bond to the next. The outside strands do not have the adjacent strand to constrain it so its over sized. It would be nice if the slicer program had a compensation parameter to control this. What I do is for interfacing parts is offset the edges inward that 0.005 inches and the parts fit perfectly.