The most inboard bracket on each wing utilize plate nuts mounted on the aft side of the front spar. Pilot holes are provided in the spar for mounting the plate nuts. The plans call out solid rivets but the access for a bucking bar is limited due to the close spacing of the ribs in the wing walk area and other builders have had trouble with them. I utilized an approach from a friend's build log (Steve Lynn) to use pulled rivets for mounting the plate nuts. MS-BK-319's are 7/64" diameter and were used in the empennage for skin/rib connections in tight areas and skin/skin connections (I think) for the trim tab. With a machine countersink on the forward side of the spar, these rivets can be flush mounted just like a solid rivet. Steve had cleared this with Van's tech support. It makes sense, as the rivets are only to hold the plate nut in place. Not sure why, but it was tough to get the holes big enough in both the spar and plate nuts to fit the rivets. My 7/64" drill bit just wasn't big enough or something..
