All the talk about T&G got my brain cells all aflutter again. When I built my Kolb tail surfaces I hacked and chopped out a simple and ugly tool that allowed me to match drill, and achieve better results than I should have gotten in the amount of time spent. Now with all the printing of assembly aid tools and clever people who can actually do it, I want to re-introduce the idea to the people who can actually make a legitimate version pf this tool.. There ought's to be... a channel or grooved block of some sort that has an extension to one end of it, and the extension should have some sort of small drill bushing in it. Actually two or three drill bushings to establish rivet spacing. So you have a piece of tubing laying down on your workbench. Sitting on top of this tube is a sheet metal gusset.You lay the tool down on the tube, with the "finger" or extension overlapping the gusset. The tool puts the drill bushing over the gusset, and centered on the (not visible anymore) centerline of the tube. So when you drill through everything, the rivet hole goes through the gusset and the tube together, and the hole is centered on the contact patch of the tube, not offset. So your rivets are as good as they can be. So if you are NOT building a CAD/CAM T & G fuselage, you can still achieve a very clean level of riveting workmanship without any of the holes be ing pre-drilled. I'm guessing that even with a partially CNC'ed fuselage kit, there are still some gussets that will have 90 degree bends in them (for inboard longeron/upright/cross-member joints), or gussets that overlap more than one part, where it is too much trouble and trial/error to have everything perfectly match-drilled ahead of time. Anyone else think this idea is good/bad/brilliant/ridiculous?