Three additional pieces were added to each side of the main beam. A piece of 1/2" plate was cut to just fit inside of the well formed by the upper and lower stiffeners, the back of the beam, and the front of the window. Additional 8" tall pieces were cut to be placed over the and below the stiffeners. These three pieces were then fitted as closely to the center of the beam as bossible and welded into each side. This resulted in the center of the beam being about 1 1/2" thick through the center 24 1/2" of the machine. Finally, the side plates were welded into each side of the window.
A note of some small caution: The welding on this project often required three or more beads per weld. One press was built with a stick welder, and the other with a MIG welder. It's a lot easier for the relatively inexperienced to do it with MIG.