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I'm getting ready to close up the aft fuselage on my A-model Sonex, and some of the holes are coming up "half-blind", and no amount of tugging and pulling will make them line up. This plane was mostly built 20 years ago, and has been moved a couple times, and the lower edge of the aft fuselage re-riveted as the original builder used -42s instead of -44s to attach the skin to the longerons.
The joint I'm most concerned with in between the splice plate, aft spar flange, a little spacer plate/shim and the lower skins of both fore and aft fuselage. The skins and the spar aft flange are finished drilled to 1/8", and they DO NOT line up with the splice plate. I'm fixing to redrill at #30 using a strap duplicator, favoring the existing holes in the splice plate, but that will leave misshapen holes in the skin a pulled rivet will NOT fill. In theory, I could use solids, I suppose, but I really don't have the skill set (I've got the tooling, less the compressor) to pull that off. I was about going with one of the following (up-sizing the holes as required):

5/32" Stainless Steel pulled rivet, standard head
1/8" SS pulled rivet, BIG HEAD
5/32" Stainless Steel pulled rivet, big head
MS24693 of the smallest size (6-32), nut, washer
AN3 bolt, nut, washer
3/16" Avex Aluminum rivet

Has anyone done something like this? I'll be sending this query to Sonex as well, and will tell you what they tell me.

AN525 washer head screws should be suitable since they are used in exactly that application on the Sonex. Even better would be Hi-Lok fasteners, although they are tricky to specify. If you need to go even bigger than 3/16", the Hi-Loks come in oversizes. Since this is a shear joint, ideally the hole should be reamed.

Peter

Kerry got back to me in a flash, he said the smallest oversize standard head SS rivet I can get a clean hole in all the pieces.
I hadn't thought about reaming. I have some small reamers; that could be the best way to get a clean, concentric hole.
The "athwartship" tab of this splice plate is narrower than the bit that gets the machine screws, and the flange of the spar is also rather narrow, so I can't hog the holes out too much. The spacer plate is only 5/8" wide.

The holes may have lined up at one time. It is possible all the holes are correct, and the builder started to rivet without clecoing beforehand and things started to "walk" out of alignment. You might think about removing some rivets and see if you can get the holes lined up.

What I ran into was the lower cross tie (F-SNX-F24-05) pre-drilled holes were off and caused the overall width of the fuselage to be too narrow, not allowing the belly skin holes to line up with anything. Same factory pre-drilled 1/8in holes.
I re-made the cross tie and all was well. You can tell if this is a problem by measuring the width of the fuselage at that location. It should be 40in. Anything less will not allow the belly skin to fall between the side skins at the lower longerons. I've noted in the past that others have had to trim the belly skin to fit.
I still have the faulty cross tie in my "Hall-of-Shame" collection.

Area 51% wrote:What I ran into was the lower cross tie (F-SNX-F24-05) pre-drilled holes were off and caused the overall width of the fuselage to be too narrow, not allowing the belly skin holes to line up with anything. Same factory pre-drilled 1/8in holes.
I re-made the cross tie and all was well. You can tell if this is a problem by measuring the width of the fuselage at that location. It should be 40in. Anything less will not allow the belly skin to fall between the side skins at the lower longerons. I've noted in the past that others have had to trim the belly skin to fit.
I still have the faulty cross tie in my "Hall-of-Shame" collection.

Ah!
Last night I cleco'ed the aft ("belly") skin onto the fuselage and everything lines up pretty well, EXCEPT the Port Forward corner lower cross tie area (the Starboard side is fine...). It's already bolted and riveted to the forward fuselage, but I THINK I can get it out by drilling the rivets and removing the machine screws, remake it, finish drill it once it's at least cleco'ed into place. That is probably the cleanest repair I could make.

I love this forum; between your experience and Peter's, I've already got two ideas I would not have come up with on my own.