From old threads it appears the official definitions of fabrication and assembly are not cut in stone. Building a 14, Van's has done a lot of work that older kit builders needed to handle, but still it's a lot. It feels like deburring alone is 30 to 40% of the build, and that riveting, where I've drawn the line between fabrication and assembly, only begins after you've done 80-90% of the work. I suspect the definitions of these things aren't as critical to the FAA as showing the work (51%+) that you did, but I'm curious: Where do you draw the line?
Cutting parts with a band saw and trimming them - Fabrication
Edge deburring - Fabrication
Temporary assembly and match/final-drilling - Fabrication
Disassembly and hole deburring - Fabrication
Dimpling and countersinking - Fabrication
Scuffing, cleaning, and priming - Fabrication
Final assembly and riveting - Assembly
Bending leading edges - Assembly
Cutting parts with a band saw and trimming them - Fabrication
Edge deburring - Fabrication
Temporary assembly and match/final-drilling - Fabrication
Disassembly and hole deburring - Fabrication
Dimpling and countersinking - Fabrication
Scuffing, cleaning, and priming - Fabrication
Final assembly and riveting - Assembly
Bending leading edges - Assembly