This particular stencil is probably the most interesting of the 52-Set stencils I am aware of to date.
As you can see in the photo of the original surviving markings, it is not a true stencil marking, but some form of silk screened product, perfectly centred on the upper left side of the Carriers No. 4. The characters are definitely all 1/2-inch in height, but slightly slimmer, and without the webbing the stencil cutting machine produces. The line lengths are a very close match but the overall height of the three lines on the stencil is 1/4-inch lower than the actual markings on the Carriers No. 4. Also, there is no means of cutting a lower case, underlined ‘o’ on a stencil machine.
When I started this project, I assumed Canadian Marconi Company built everything for the set but actively contracted out for components. I am not sure why I made this assumption considering I knew Northern Electric had built the Supply Units for the earlier No. 9 Sets made by CMC.
I have now learned RCA and Philco were clearly providing major sub assemblies and accessories to CMC for the 52-Set as sub-contractors. The sheet metal work required for the chassis of the Receivers, Supply Units, Senders and Coils Aerial Tuning (and probably the Remote Receiver Case) would certainly be within the capacity of Marconi’s shops to have produced, and with the exception on the Remote Receiver Case currently soaked with NATO Green paint, all the other chassis bear CMC inspection stamps punched into the metal.
The Carriers No. 4 is a somewhat different beast. Although the basic three compartment box is the same gauge metal as the chassis items, the Carriers No. 4 has some very heavy duty steel formed and fitted to it. It would not surprise me at all if the Carriers No. 4 were sub contracted out by Marconi for production and whatever company manufactured them used silk screen style tools for the markings. When I eventually get to the point of restoring the Carriers No. 4, perhaps some stampings will show up on the metal parts somewhere that will shed more light on this bit of 52-Set production.
In the meantime, I now have a stencil I can use for this marking, if all else fails, and enough time to explore silk screening options a little more to see if there is a way to easily replicate this item.
David
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