Hi Bob.
This is proving to be an interesting side step in the 52-Set Project.
Canadian Marconi did a fantastic job of researching the needs of the Wireless Operators in the Canadian Army as they proceeded with development of the Wireless Set No. 9 series of equipment leading to the No. 9 Mk II/52-Set. I suspect overheating of this equipment was not so much an issue in normal environments but was very likely at play when operating wireless gear in the desert or tropics where ambient air temperatures exceeded 100 degrees F. Their use of thermal cutoff switches for the two dynamotors if they overheated and the activation of the two blowers to increase airflow in the Carriers No. 4 Compartments compliment their decision to use Grade 4 High Temperature grease in the dynamotors. Once Robbins & Meyers had tweaked their two dynamotors, a very solid product emerged. I tend to forget sometimes my 52-Set will never again be operated in such extreme conditions so side-stepping the Grade 4 grease should not be an issue for the limited future use the set will be subjected to by me. It is interesting that one of the Modification Orders for the 52-Set issued in the late 1940's or early 1950's was how to relubricate the set so it would function reliably in the Canadian arctic. Perhaps for Operation Muskox and similar exercises.
The last time I re-greased bearings was on my M38Cdn and 1944 Chevy C15A Wireless. That involved the simple set of metal cones on a bench with the central hub lube fitting and a grease gun. I would be surprised if the bearings in the two dynamotors were large enough for that type of equipment. At this point even, I am not sure of the bearings are even ball or roller style, though I am leaning towards ball. The service instructions nicely lay out how to remove the two dynamotors with the Supply Unit on the bench, without removing electrical connections and opening up the end caps to expose the bearings for work...but not the work itself. So bit of a mystery there at the moment.
I also need to find out if the end cap sealing material is still available. It is that thin but very stiff, smooth tan board stuff. One dynamotor used rings of it the other solid circular discs.
It is nice to finally be gearing up for work on the Supply Unit, but ohhh, the adventures!
David
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