Dad and I deburred the edges and lightening holes of all the ribs prior to starting the assembly of the tail structure. For the most part, everything lines up with amazing accuracy. It something isn't fitting, it's likely that you've made a mistake! The main ribs and nose ribs are clecoed and match drilled.
All of the main ribs are identical, but the direction the flanges face can vary. All of the main ribs except the two inboard ribs have flanges facing outboard. The two inner rib flanges face inboard, plus those ribs are not at 90 degrees. They have an angle to them, but that is easily determined and set once the ribs are clecoed between the front and rear spar.
Sadly, after everything is put together, it's time to take it apart (the first of many times). At this point, we deburred all of the edges, match drilled holes, and lightening holes in the spars and deburred the remaining holes in the newly match drilled ribs.
Van's supplies a couple of pieces of plywood with a template drawn on them for jigging up the horizontal stabilizer. We cut out the templates and screwed each to 2x4s. The templates were then clamped to the bench after squaring them to each other. We started on the right side first - setting the skin in the jig first (taping the trailing edges together to keep them from kinking) and inserting the nose ribs. Most nose ribs fit quite well after rounding off the front flange a little bit, and it took minimal pressure to line up the holes and cleco. After the nose ribs are clecoed, the front spar is inserted and clecoed, followed by the main ribs and the rear spar.
The only side that really caused any trouble was the inboard-most rib where it attaches to the front spar. All holes lined up perfectly except for this single spar hole. It took a considerable amount of twisting to get the spar hole to line up. I don't want to rivet it under tension just because the spar might have a very slight twist to it, so instead I drilled it to match (considering every other surrounding hole fits perfectly). I'll take a look at the hole once the assembly is taken apart. If it's elongated at all or too big, I'll upsize this rivet. Either way should work just fine.
Tomorrow Dad and I will take the right stabilizer apart and start deburring and dimpling all of the parts. We'll then move along to the left stabilizer and repeat the entire process.
