Well, after stewing for two weeks over the messed up root rib, I finally diagnosed the problem. The rib is mounted based on a measurement of 9/16" forward of the rear spar. I made the conversion to 32nds correctly but selected the wrong cardinal measurement on my steel ruler. I marked 16/32nd rather than 18/32nds. I did it twice and I still didn't detect the mistake until the third check of the measurement!
Well, I fabricated a new root rib, cannabalizing the the reinforcement angles from the first try by drilling out the 10 rivets. I'm getting good at drilling out rivets without enlarging holes. That was not a skill I intended to master when I started this project.
This little fiasco wasted a lot of time and effort. Hard lesson learned.
Finished up by adding ribs 1 & 2 and attaching the inboard nose ribs but developed a new problem. My rivet gun snapped the mandrel on several nose ribs 1/4" above the rivet head and four did not set flush. The tight spacing makes it very difficult to get the gun into the space. Drilled out the upset rivets and used a Dremel cut off wheel in my air drill to cut the mandrels off flush then drilled them out. This turned out to be a very long day for what should have been really simple work.
Root rib; the blue line at the top is the wrong measurment.
