How does one assembly the twelve edges of the cube, along with four diagonal pieces? First, get yourself a three-way right-angle fixture and weld up four corners:

Now, each of three cubes has four faces with diagonals, and two adjacent ones that are open. The seven tubes surrounding the open faces get 0.12″ wall, and the others get 0.08″. That means that each cube gets one vertex with all thin, one will all thick, and two with two thick and one thin. Blake has to put all that together, along with the diagonals.

Blake doesn’t much like to talk about what happens next. I just inspect the results and make sure that everything is within tolerance. Everything important on the cube is within 1/8th. (That’s a 40″ cube with 1.5″ OD.)

What is important is that we have a nice square corner and well-placed flanges, which we’ll talk about next.

Beeuuteeful