I wasn't happy with the r/h lower instrument panel angle. somehow I mis-located it when I drilled, and it was about 1/8" fwd of the other side. The panel tightened down on it just fine, but I was afraid that I would be able to see a bow in the instrument panel in that corner once I peel off the blue vinyl, or that it might cause some other problem on down the road. The time to fix it is now while it's ll just clecoed together.

The holes were already match drilled in the supporting structure, so just relocating the angle wasn't an option, but I was able to use the old angle to match drill a new one with the holes at minimum edge distance from the fwd edge of that leg of the angle (.219 per mil spec) which had the net result of relocating the other leg aft an appropriate amount and that pretty much eliminated the issue. At this point, the difference between the two sides is only 3/64, which is as close to perfect as I'm likely to ever get.

Now it was time to get back to the fwd skin access panels. After thinking about it, I decided that the reason so many of the panels I see on completed airplanes are pooched up between the screw heads is likely because guys lay down a thick bead of pro seal with some plastic wrap to make a gasket (following the instructions) and then 90% of it gets squeezed out when they crank down on the screws to get them somewhat close to flush, but it can't all ooze out, so it causes the bowing.

Based on the thickness of all the respective sheets, the panels are flush with the skin without any gasket material at all in there, so any way you look at it, gasket material will make the covers sit proud.

With that in mind, I went ahead and fabricated some .025 spacer rings that will go between the skin and the nut plate rings to make the rings sit .025 lower than the surrounding skin. The idea is that when I make the gaskets, I can just tighten the screws until the panel is flush with the surrounding skin and that will leave me a nice .025" thick gasket to keep water off my precious avionics, while allowing the panels to be more or less flat between the screw heads.

A while back, I was getting ready to install the upper fwd tailcone skin and noticed some damage on it, so I ordered a new one. The damaged one has been on deck to be cut up for something ever since, and it's .025" thick, so it was perfect for this. I traced out the nut plate rings from the kit and cut out a chunk with the air nibbler that I recently got at harbor freight for this kind of thing. It makes nice cuts without distorting the surrounding material like shears can, and it's a ton faster than a hand nibbler, but holy cow, does that thing make a mess! It ejects tiny little aluminum toenail clippings as what seems like mach 2, and they go everywhere, but there's something very satisfying about using it.

Once I had a chunk of manageable size, I cut to the exterior line on my band saw, then match drilled to the nut plate rings from the kit. This allowed me to position the covers and trace the interior cut line so the finished product will be the same size as the hole in the skin. I then rough cut the interior hole, again using the air nibbler to get close, then snips, then took a 1/2 round vixen file and finished by carefully filing away the sharpie line I had traced earlier.

This was a ton of work for something so simple, each one of these simple little spacer rings took more than an hour to make, but the end result will be worth it.

A trial fit revealed a couple of places where I needed to take a few thousandth more off, but eventually, I got them as perfect as I'm capable of making without CNC equipment. Once I was happy with how everything was fitting, I took it all back apart, which is typical, but still seems like a step backward.

I had some time left in my day, so I deburred the access panel components and interior of the skin then prepped and primed those components.