That brought back memories - I once saw a 10" ish polisher - wirebrush - grinder in an old blacksmiths shop that used old CI pistons as bearings with built in support, 3HP motor.
Apparently it had run over 15years on the original pistons.
''oh yeah'' said a sceptical and green Sami,..the old timer tapped the side of his nose and took the cover off one of the pistons.
The inside was filled with cotton waste and oil,....... as near as no play in the bearings either - red face time
That old timer knew a thing or two,.......... strapped for cash after the war, he'd used his skill and knowledge......... though he had the grace to admit that when he built it, he told himself ''it would do until something better turned up''