Verified the angle between the forward spar and rib #7 was 71 degrees. To do this, I used trigonometry to draw on my work table a line that made an angle of 71 degrees with the edge of the worktable. I then clamped the vertical stabilizer front spar to the edge of the worktable and positioned rib #7 so that it was aligned to match the 71 degree line on the worktable.
Transfer drilled rib #7 to the front spar.
Disassembled and de-burred the front spar components.
Smoothed the edges of the front spar and the ribs. Smoothed the edges of the lightening holes in the front spar and in the ribs.
