Riveted in inboard and mid 904 main ribs to the spar, and riveted the skin to the spar on one side with the help of Noah Schwab, the 8 yo son of a friend, who wants to go to the AF Academy someday. He put in rivets and taped them down while I bucked 'em. Then he learned how to take out cleco's and put rivets and tape on those. He did a good job and had a good time. I was worn out but he was ready to keep going. I messed up one rivet near the edge when I used the pneumatic squeezer and didn't adjust it properly, resulting in a rivet shop head that was over squeezed. I drilled it out no problem, and re-squeezed it, no problem.