Hi-
Last year, I picked up a CTC-4 that was missing its back cover (and had a broken CRT neck), and I just recently decided to make a replacement back for it, before installing a replacement CRT. Bob (ohohyodafarted here on Videokarma) had one made for his Hallicrafters CTC-4 "clone" set as described here, at a CNC shop:
http://antiquetvguy.com/WebPages/The...-21CK801M.html
A professional reproduction like that is out of my budget at the moment, but with hardboard panels available for $8 that are big enough for four backs, I figured I would try making my own, and in the process get all of the measurements needed to get quotes from local CNC shops or owners myself. I made my measurements from a combination of my own CTC-4, Bob's pictures, and Phil Nelson's pictures on his site:
http://antiqueradio.org/RCACTC-4ColorTelevision.htm
Below is a picture of the result; it is not perfect, but good enough to use until I get a machine-cut one made. More details are available here:
http://70.36.238.5/ctc4back/
Regarding commercial fabrication by a CNC shop, I remember reading of at least one other CTC-4 owner needing a back, so maybe I should find out if several can be made at a cost savings compared to just one or two. The one change I made from my measurements (which are only educated guesses, without access to an original) is to increase the height of the back panel from 23-3/4" to 24 inches, because my set's bottom-edge screw holes were made into the edge of the plywood platform that holds the chassis, and they are not very secure as shown in the other picture below. Adding a quarter-inch allows the screws to be put into the solid wood strip on the bottom edge as they are on the top edge.
I would appreciate any comments on this work, or my plans to get cost quotes. Once I transfer my hand-made measurements to some electronic form (whether just a graphic image or a CAD file of some sort), I will be happy to share them with others here.