Ribs riveted to the elevator skins. Rear spar riveted to ribs. Shear clips in place, gussets in place. Had some great help from Daniel and Audra today. Audra was instrumental at removing tape from rows of rivets after having been set by the back-riveting method. Daniel has an excellent sense of timing. When back riveting using the C-Frame tool as described the other day, there is no effort required to center the rivet gun. You just align what you want to rivet and pull the trigger. To get the rivet set perfectly, you hold the trigger down for the right amount of time - maybe 1.5 seconds. I showed Daniel what to do and let him pull the trigger. After each rivet, I checked it with a gauge and when necessary had him hit it again. After he got the timing, the rivets were just about perfectly set every time.