I have started riveting the center ribs. As stated in the last post I had to fabricate six flanges to get the edge distance I wanted. The edge distance is a measurement of the center of the rivet hole to the edge of the material. Minimum distance is 2X the diameter of the rivet and 2.5X is recommended. The flanges were right at 2X, right at minimum. Which is airworthy and would pass any inspection. But if the rivet is set in a way that it needs to come out now you have a problem. If when drilling the rivet out the hole is oversized you need to go to the next size rivet. But now you won't have 2X edge distance. So I just decided to remove the flanges, make new flanges that were slightly wider and back drill them into place. Once those were removed and the new flanges in place I could rivet them to the spar and move on to the center ribs.
The wing will be relatively stiff once the ribs are riveted to the spars but not rigidly. You can still move the spars slightly to eliminate twist in the wings. But it is better to start riveting with the wing straight and true without any twist. So I spent about an hour checking measurements to make sure I started with the wing straight in the jig. And I repeated the measurements three times, which is the best way of determining if I am measuring consistently.
By the time I was done with all that I had limited time left to rivet. I only got one rib riveted top and bottom. Part of that is the process I went through to determine the best method to rivet the ribs. If at all possible I use my pneumatic squeezer. Once it is adjusted for the rivet size it sets beautiful rivets, consistently one after another. Just make sure you are square to the rivet and pull the trigger. But it is a large, heavy tool that does not fit in all places. I tried to use it in several locations on the ribs but found it just did not fit 40% of the locations; wasn't square to the rivet, other rivets on the spar kept it from getting to the rivet or the space was just too small.