That's just building, shall we say, two steel wing ribs to be used for patterns for making balsa ribs. I sandwich the balsa rib blanks between the steel rib patterns and sand them down. The patterns and two lengths of drill rod are the jig. I have various lengths of plastic standoffs (2", 1",1/2" and 1/4") to space the ribs. This allows any combination of spacers to be used to correctly space the ribs. The standoffs are 1/4" ID and 5/8" OD. If you are building a wing with a 2" space between the ribs, slide a rib on the drill rods, then a 2" standoff on each drill rod, then a rib, then a 2" standoff on each drill rod until all the ribs are on the drill rod. On the outside of the first and last balsa ribs, I use a one inch standoff and a 1/4" steel collar, steel rib pattern, and another steel collar. Square up the steel pattern on one end of the wing. Get all the play out of the ribs, spacers and steel patterns on the other end of the wing and tighten the collars. The ribs will not move and are spaced correctly, square and vertical. The flat bottom of the rib pattern sits on a flat surface. This is the jig. Washout may be built in by shimming up the back of one of the steel rib patterns.

If you could see this, everything would be perfectly clear.

Zor, I have a Mac and don't have the high dollar photography software. I have never figured out how to size photos that are acceptable for most sites. I'll try a cell phone and see what happens.