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Originally Posted by cletrac
Chris, you're right but did they have both those kinds in the late 30s? lol By the mid 40s plastic had advanced by leaps and bounds!
I got one switch mounted today. When I'm done and paint stuff black it'll look the same whether plastic or metal.
I've been pondering the construction of the doors. In our picture of them it almost looks like the edge of the left door is bent funny but I'm not sure. The light is coming from the right so the black line you see has to be the gap between the doors.
I'm going to make the doors out of 14 or 16 gauge. They wouldn't be heavier or they wouldn't need the edges folded back that inch or so. That open catch hangs down over an inch so it has to be mounted an inch and a quarter or so back from the face of the closed door. That makes the door an inch thick. The doors will look like a shallow box.The doors don't overlap the unit's sides or they would tangle with the hool up cables.
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They had bakelite (phenol-formaldehyde + various fillers) plus all its derivatives (Paxolin - synthetic resin bonded paper, and Tufnol - synthetic resin bonded fibre) and various other engineering grade plastics in the 1930s - remember that telephones were no longer made of wood!
As for the doors: STOP!
They will be thin sheet steel with a folded edge of 1/4" maximum to provide stiffness and enough overlap when closed to exclude dust. The closing edge of one door will have a step rolled/pressed into it so that it overlaps the other door when closed. The securing clips are a three part construction - a bracket that is spot-welded (or soldered/brazed) to the case, an thick wire loop that acts as a hinge, and a shaped spring brass clip.
I'll get the camera, some spare valve/spare parts cases and a Switchboard UC 10-line out in a bit for some typical construction details.
Chris.