Today was finally the day I got around to fabricating a replica back for this set
Although some came with a perforated metal back, there was also a masonite version.
I no longer have mine, but I made a template before I sold it. Then the hunt was on for a small metal CRT cup. I tried search ebay for things like metal ashtray and finally came up with these vintage mini pie tins that are almost exactly the same dimensions as the original
Time to get cutting. It's not so bad if you use a fine toothed blade in a table or circular saw.
Making progress. It actually took longer to mark out the holes than to drill them. I used a drill press and a 3/16" brad point bit. I think a little larger 1/4" bit would have been closer to the original.
It only took about 15 minutes to drill all the holes.
Here's the completed back installed on the set. The pie tin is held on by four button head screws.
Overall it was about three hours work. I think I could make another in half that time now.