I got the F-1046 longerons clamped in place and ready to match drill the holes from F-1005E gussets. It is a bit awkward to access with the skin in place and had to use a 90 degree drill to get to it from the bottom. The very first hole I drilled in the left longeron came up through the longeron and I could tell the edge distance was no good - measured at about 3/16" to centerline. Maybe the drill was not perfectly perpendicular to the part - hard to tell since I was drilling somewhat blind from the bottom. Proceeded to drill the remaining holes and they seemed better, but still a little less than ideal edge distance - was measuring about 7/32" from edge to centerline of hole. That's a little less than 2 diameters. What is going on here? When I measure from the inside edge of the skin to the holes in the gusset plate, I get about 17/32". It's a 3/4" angle, so that leave 7/32" edge distance. I looked at some of the other holes along the longeron and some of those are also about 7/32", and those were drilled with the template. The left one is definitely trashed, but the right might be ok - seems about the same as some of the other holes.
I sent a note to Van's to be sure I've got this right before I mess up one of the long F-1013 Longerons. In the meantime, I was able to source some 3/4x3/4x1/8 6061-T6 aluminum angle locally at Metal4U. $20 for two 5' long sticks.
Already got the new left longeron bent to the template and ready to match drill again.
5/11: warm muggy night, a sign of the months to come. But I got the longerons redrilled and they came out much better. I measured and drew a line 1/4” offset from the holes on the gusset and used that line to align the longeron. Turns out the bulkhead that held the gusset could twist a little and must have out of alignment the first time. With my marks lined up I drilled it with the air drill from below. Perfect.
Proceeded to match drill all the #40 holes from the mid fuse skins to both longerons.
Purchases: Metal4U - Aluminum angle stock