3/14/2021 – 3.3 hours There are several unique riveting situations involved with the left and right elevator root ribs. Pretty much every type of riveting situation I've seen to date happens in this step, as well as a couple of new ones. The first challenge was to rivet the aft flange of the left root rib to the rear spar. That seems like a straight-forward task, but the angle of the rib makes for a very constrained area. I decided to put the manufactured head on the rib flange in keeping with the practice of the manufactured head on the thinnest part. In hindsight, it might have worked better to drive the rivet from the spar side. I tried to use the pneumatic squeezer, but the poor access led to a bent rivet and 30 minutes of carefully drilling out the bent rivet. The plans say you can use a flush rivet set on the manufactured head of an AN470 rivet in tight areas, so I decided to go with an alternative form of backriveting. I used the angled face of the bucking bar against the manufactured head of the rivet as a back rivet plate, and drove the rivet from the shop head side with a short back-rivet set. The rivets aren't perfect, but they are acceptable. The next challenge was to rivet the gusset to the rear spar. This challenge involved very carefully lifting the skin away from the structure to get a bucking bar behind the rivet, and then driving the rivet with a 1/8” cupped rivet set through the spar. This operation is all done by feel, and you have to take your time to avoid damaging the top skin that is lifted up or the bottom skin if the bucking bar gets dropped. The final steps for the left elevator was to attached the Reinforcement Doubler Brace to the Left Root Rib with two blind rivets, and then to rivet the upper and lower flanges of the root rib to the upper and lower elevator skins. There weren't any surprises with either of these operations, and they were completed without incident. Like the left elevator, the right elevator root rib had its own set of riveting challenges. Riveting the gusset by lifting a corner of the skin was the same as the left elevator except now the gusset had to be riveted to the root rib instead of the rear spar. With the gusset in place, it was time to break out the special RV-14 Elevator Bucking Bar to rivet the final 3 three inboard holes on the bottom skin to the rear spar. These are left open to allow you to lift the skin for the gusset rivets, and can be closed at this point. I reconfigured the work bench for the rear spar rivets including the shim under the spar to allow movement of the bucking bar without damaging the trailing edge. I added a new twist this time that I wish I had thought of earlier. Instead of using the edge of the table as a fulcrum for the bucking bar, I placed an eraser under the bucking bar just aft of the trailing edge. The eraser was an excellent fulcrum, and it provided exceptional lateral stability to keep the bar from sliding and twisting. The last three rivets were very easy to set with the eraser in place. The aft 2 holes in the top and bottom of the root rib (4 holes total) were final drilled #33 in preparation for blind rivets in a later step, and the upper and lower flanges of the right root rib, with the exception of the aft 3 holes (top and bottom) were riveted to the upper and lower elevator skins. [3X Rivet Gun, Back Rivet Set, 1/8” Cupped Rivet Set, 3/32” Cupped Rivet Set, Swivel Flat Set, Small Tungsten Bucking Bar, Medium Tungsten Bucking Bar, Special RV-14 Elevator Bucking Bar, Rivet Puller, Pneumatic Squeezer, Large Diameter Squeezer Sets]