Here is what it looks like now. The right side has a new back, the perimeter is original, and hammered close to original shape, with minor imperfections. There was a missing section of the perimeter on the lower left part, so that part had to be cut, bent, and welded in. Next the weld has to be cleaned up on the inside of the box, since the weld penetration shows through a bit. I'll do this very carefully with a carbide buyy on a die grinder.
The left hand side was very beat up. like someone used a baseball bat. I decided to save this side, as it has no bad rust, and too many tool hangers to remove and re-weld to a new back. I started off with a doube ended hammber, and used a dead blow hammer against the hammer to provide the blows, as I couldnt swing the hammer in many areas due to the tool hangers. The hammer could only help smooth out lumps, and prepare the damaged metal for shrinking. You can see all of the spots where I had to shrink. A no crown pannel is incredibly hard to straighten, especialy when is 22 ga steel. Im amazed they made these so thin. I got is 70% better, and then focused on truing up the perimeter.
I know it will never be perfect. Its 83 years old, it should look perfect. The right side back will almost look too good, but with all of the tools in it, you wont see that the right side back is perfectly flat.
From here, I will straighten out the shelf unit and hangers that I just had a friend bead blast, and spot weld them back in. From there I will bead blast the entire unit, and have the paint shop match the original olive green color off of my dealer box where the original paint is in good shape.
As of tonight, but still more work to do: