Step 3: Assembly
Screw one end of the threaded rod through the top piece with visegrips.
Slather up the finger joints with wood glue, and some dabs of urethane glue (like Gorilla glue), which will expand in the presence of moisture to fill the voids and gaps in the joints. Clamp end-to-end. A spreader may be needed at the feet, as they will have a tendency to lean inwards.
Screw the rod through the hole in the leg. Lock the threads at each junction by working some urethane glue into the holes.
You may or may not want to glue a little beveled strip on the inside of the joint for extra strength.