Wing Spar Countersinking and Nutplate Fixing

Today I got started with all the wing spar countersinking.....after the screw holes are countersunk, that will have been about 554 holes countersunk give or take a few.

So Vans has you countersink all the nutplate mounting holes flush.  They also have you countersink the holes that just intersect the ribs and spare flanges flush since they don't go thru the skin.

Next they have you countersink the rest of the 3/32 holes -0.007" from flush that have rivets that come thru the skin.  There are a bunch of them!

Next I spot primed all the nutplate mounting holes with self etching rattle can primer.

 And then deburred all the nutplate mounting holes on the back side.

Finally I placed all the nutplates, ready for riveting and ran out of time!

Right wing spar to J stiffener drilling

Right wing J stiffened all drilled!

Wing spar match drilling to wing J stiffeners

So for some weird reason Van's has you use the wing spar to match drill the holes for the wing skin J stiffeners.  I imagine they have you do this because it is hard to do it the old fashioned way by aligning a center line in the wing skin holes.  I guess it is too far to expect someone to be able to reach or something.  Anyway some people have made a mistake here and mis-drill these.  Thankfully I read about that elsewhere before and this was not a problem for me.  Thanks to all the people that came before me!

They have you clamp the stiffeners to the wing spar flange.

The stiffener should stick up above the spar flange by 1/16".

Then match drill it to the spar flange holes.  I used a cleco in every other hole.

Yep, that is a bunch of holes!

For the bottom side, they have you skip the area that gets inspection plate nutplates.  Those don't exist on the wing skin where the J stiffeners go so you don't want those holes match drilled here in the wrong place.

Both sides done.  Something like 164 holes per spar!