Why are HS spar flange holes smaller than skin holes?

Anyone know why the HS spars are drilled smaller than the skins? By eye I would say the spars appear to be #40 rather than #30 as in the skins. Mine are a little out of alignment and I fear the spar hole will center the drill more so than the skin hole causing the skin to be drilled slightly oblong since the holes in skin and spar are not concentric. Anyone else have this “problem?” Or did the drill center in the skin enough to not allow the spar hole to move it off center? I am hesitant to try to move the skins enough to try to align the holes, if that is even possible. Or did you remove the rib clecoes, drill the spars and then adjust the ribs to match their skin holes?

1 answer1 reply

2 Comments

Ryan

Sep 23, 2020

M.whiting,

The holes in the spar are intentionally undersized to allow for slight misalignment. You should have no issue transfer drilling the spar through the skin. Hope this helps and happy building!

Thanks,

Ryan

m.whiting

Sep 23, 2020

Replying to

Thanks, Ryan. The misalignment is small, probably 10 thou or less, but definitely noticeable to the eye. I wanted to be sure this would not cause issues before drilling a bunch of holes!