Rudder 3...

As the rudder started to come together, it became very evident that holding the pieces down was going to become extra important. I was able to fashion some wood blocks to sandwich the rudder spar. Then I clamped those pieces to the work surface. That worked pretty well. Once I started working with the skins, I had to modify just a bit.

 This worked well initially. Especially when driving the rivets for that rudder horn (the thick machined part at the bottom)

Various doubles and nut plates get installed to attach the rudder. Simple...

 This is when the rudder really starts to take shape. It went together VERY easy...

I prefer to label all of my parts with a sharpie. It keeps it straight in my mind... Your mileage mar vary...

 Then, it happened... I realized I screwed up the hole for the rudder counterbalance. See the two dimpled holes on the bottom? they are supposed to be on top. (whoops). I called vans and they said just punch a new hole, dimple, then build on. Lesson learned, look at the part depiction in the instructions ten times before drilling...

Next, there was a brace at the bottom of the rudder horn that required some massaging. Its kind of hard to see in the pics, but the part labeled R910, did not sit flush with the rudder horn. But, because it is riveted on the front, both sides, and the bottom (to the horn), you better make sure the part fits perfects before banging away. I lined up the part in the skin ribs, and then the web adjacent to the skin ribs, and discovered some "massaging" needed to be done where the part hit the rudder horn. Using a hand seamer, I carefully adjusted the radius on the tab that extends to the rudder horn. It fit perfectly, it just took some time. 

The next magic trick came when tyring to buck the -4 rivets behind that R910 gusset/bracket. I strongly urge you to use padded envelope material that is cut to fit. If not, the bucking bar will make a mess back there. I also used a tungsten bar, I have no idea how a steel bar would perform in such a small area. 

Before the R910...

 Figuring out that the holes didn't line up... Also, a great view of the hole that you have to fit a bucking bar into.

Now you can see the bottom "tab" sitting flush 

 Cleco until you are blue in the face.

Now, after we know it all fits together, it all gets taken apart, after drilling the holes to size. Then it gets deburred, and dimpled. It sounds simple, but the skin is .016" thick, and it seems like you are working with tin foil. 

 The only way I could keep from going too deep was twisting the deburring tool between my fingers. After hundreds of holes, I got a bruised thumb, but the work turned out awesome. You can just see the chamfer in the hole to the left of my tool.

Dimples for the skin. Super straightforward. This DRD2 tool produces excellent consistent results. 

Now, this is the first part of the build I will bag on Van's just a bit. The trailing edge "wedge" design on the rudder is poorly conceived, at best. You install a double countersink on a piece of angled extrusion. Then, you dimple the skins on either side, and rivet the whole works together. It's almost impossible to achieve a straight trailing edge.

All the angled squeezers I have seen end up putting marks in the skin.  The results are just not attractive. As for the bucking method spelled out by Van's in the instructions, I am extremely good at working with my hands, and careful with the rivet gun. Even using a 2X gun, on low pressure, its impossible to end up with a nice trailing edge on the rudder.

I have considered rebuilding the rudder, except on the new rudder, using structural adhesive just on the trailing edge. Heck, if its strong enough for Grumman to use in the wings, its strong enough for the trailing edge of a rudder....

Anyways, these pics show how you set up your drill press to do the countersinks. There is a length of that extrusion below the top portion, so the angle is correct.