That looks like a challenge! Is the chassis still sound or has it gone really weak ? I had a Sobelette radio that had a thin steel chassis that was very rusty. when I tried cleaning it I went straight through!
My physics teacher at school gave me a load of stuff when he retired including a Viewmaster he had built in the 50s he said it had been the main Tv at home for over 20 years and had only just been displaced by a colour set.
In that time he had modified it for a rectangular tube, ITV and had rebuilt the IF strip with EF80s.
It didn't have a cabinet. and used to horrify my mum when she dusted my bedroom, it was just balanced on a linen basket with a wire up to the picture rail for an aerial.
I loved watching programmes on it with all the valves alight.
One day the lopt started smoking. Once mum realised it didn't work I was under pressure to get rid so I scrapped it for parts, I remember not wanting to but I thought where was I ever going to get a lopt for it?
It was replaced with a Invicta 7070u I caged from a local TV shop, a brilliant set. I still have it 42 years later!
I still regret scrapping the Viewmaster though it was beautifully made..
Rich.