Brief Description: RH Spar Flange Countersink Drama
This entry is a compliation of the week's activities since my last entry. I ran into a problem with my backing plate method on the upper RH spar flange. About half my screw hole centerlines did not line up with the nutplate centerlines. I think my backing plate shifted causing me to mislocate the pilot hole a bit. By a bit I mean 0.010 to 0.040 in. depending on the hole.
I called Vans and they suggested I install the nutplates per the plans and use them to touch up the existing CS. The CS will be a bit oblong, but I was told that is acceptable. If I didn't do this then the skin dimples in the fuel tank wouldn't seat properly in the spar flange.
I finished all the rest of the CS in the upper flange and treated them all with Bonderite. I used a single flute countersink bit and it sure works well. It cuts very aggressively and makes very a very smooth surface. No hint of chatter.
I still need to touch up the reworked countersinks with Bonderite. After that I need to set five rivets, prime and install the brackets and install three more nutplates. That will complete the RH spar.
CS was not aligned with the nutplate. This is one of the worst ones.
After touch up using the nutplate as a pilot. You can see the slight oblong shape in the center hole.
