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Task: Drilled lower fuselage skin at wing root
spending all day Saturday mating the wings and drilling the
all important rear spar bolts, I discovered I made a mistake!
Luckily the mistake was not with the bolts but rather with the
lines I drew at the room where the open holes are for nutplates.
Rather than drawing the horizontal lines on the bottom of the
wings, I drilled them on the top. That means I had no idea where
the open holes were since the bottom fuselage skin covers them
up. Rather than pulling the wings off, I decided to try something.
I measured the distance from the screw holes on the top wing
skin to the nearest rivet outboard; it was just under 3".
I made a small metal jig of that exact dimension so I could
measure in from the same rivet line on the bottom skin. After
making a horizontal straight line on the fuse skin extended
from the wing rivet lines, I used the jig to mark the vertical
line. This worked out perfectly! I was able to easily drill
the holes #40 and then #19 for the #8 nut-plates.
other thing I did tonight was drill the T-704 fuel tank brackets
where they attach to the F-796A tank support brackets. Since
the support bracket already had a 1/4" slot, I found a
thick piece of angle and drilled an undersized hole in it. I
then clamped it to both the tank bracket and tank support bracket,
ensuring it was centered in the slot. I then match-drilled with
the undersized bit. Lastly, I used a 0.25" reamer to open
the hole up for an AN4 bolt.
We used a
piece of angle with an undersized 0.25" hole drilled in
it as a guide. It ensured the hole was drilled straight since
I used an angle drill from behind.
Next I drilled
the two nut-plate rivet holes #40.
riveted the nutplates in place. The inboard onces could be hand
squeezed, the outboard rivets had to be bucked.