While preparing to countersink the VS spar doubler, I re-read Vans’ instructions on how to countersink. Turns out I used the wrong method on the HS-710 and -714 reinforcement angles – using a male dimple to check countersink depth makes for too deep a cut.

For a hole that will accept a dimpled skin, the current instructions call for countersinking the hole just enough to make a rivet sit flush, then going another 0.005″ (two countersink sink ‘clicks’). Well, mine were a lot deeper than that. According to Gus at Van’s, there are no structural issues since the holes weren’t countersunk all the way through. Riveting the hole could be difficult since the rivet shank will expand in the area between the countersink and the dimple, but the suggestion was to rivet them anyway – four sub-par rivets wouldn’t make that much difference.

Just to be on the safe side, though, I’ve ordered a new -710 and -714. The challenge will be to make the match-drilled holes line up on the other parts drilled in assembly with these two. If I can do that, I’ll use the new parts. If not, I’ll fall back on Vans’ suggestions.