Hey Mike,
I think the '40 is like my '46, so I'll tell you how the '46 works and hopefully that helps.
The frame is two "C" shaped pieces joined by pieces of flat bar stock that are bent to make the angle. At the top and bottom of the inside of the frame are 8 flat head screws that attach the frame halves to the bar stock, 2 on each half top and bottom. Depending on if your saving the frame and glass or not will determine how you attack the problem and how extensive a vocabulary will be needed.
Steve
