Brief Description: Fabricated Stiffeners and Deburring Work
Disassembled the nose assembly and deburred the holes, inside and out, on the counterbalance tube. Getting the burrs off the inside of the tube holes is a real bear. I bought a couple of deburring blades (B30 and B60) from McMaster-Carr and they eventually did the trick with a lot of elbow grease. Steel is not a fun material to work with.
I had a lot of marks on the spar flanges from a cleco or an awl slipping out of the hole when I tried to manhandle the skin in place. They were always in the worst possible orientation too - 90 deg to the edge and right at the hole. I pulled out my angle grinder and used a maroon ScotchBright pad to carefully blend away the scratches with about a 10 or 15 to 1 taper ratio. The spar is made from 0.040 in. material so the limit on material removal was 10%. This is a typical value used in aircraft repair, but just to be safe I called Vans to see if they were ok with that limit (they were). I did measure how much I took off for every location and it never exceed 0.003 in.
Since I took off the Alclad layer blending out the scratches, I shot some SEM primer on the flanges after I dimpled all of the holes. I did find one hole that had a small crack that I couldn't blend out. I marked it to drill it out to #30 later, and I'll fill it with an oops rivet. That'll clean up the hole nicely.
The stiffeners were sanded on my belt sander down to the marks to get the final profile. I ran out of light so I'll do the final deburring tomorrow.
Stiffeners ready for the sander to get to the final profile
You can see on the hole on the right blended out & on the left with some scratches
Spar flanges primed to protect the bare spots where I blended out the scratches
