Prepared the ribs and set up the left horizontal stab for drilling: 8 hours

 

Not these kind of ribs

Here they are...

A couple of the ribs had to be trimmed precisely to fit the forward spar. The rest of the work was a lot of deburring and smoothing.

Various Scotchbrite wheels. Very helpful.

The fun part came when I go to temporarily assemble the left section to check the fit of the trimmed ribs etc. There are some tight tolerances and it seems to be a common area for mistakes. It's amazing how much helpful info people have on the web about the building process.