Here is a bicycle frame building jig I drew while in college,
it is essentially a copy of this in an 2d autocad file with some small changes and a bill of materials.
mostly 8020 extrusion with preselected hardware only thing not specified is the cone shaped bits to center the frame tubes.
This is an okay quality screencap;

Here is a rough PDF copy JigRough.pdf
Here is the AutoCad dwg file Jig2010.dwg