Blackstone Model 350 Washers
These were very cool well built machines, we have both the 250 and 350 pairs in our museum project. The BS 150, 250 and 350 were their all mechanical machines that used a mechanical timer in the transmission instead of an electrical timer. But like all 1950s automatic washers they had significant long term durability problems which is why very few 1950s AWs lasted even to the start of the 1970s.
I would wager that the cheapest washer built today will easily outlast any 1950s AW, much like new cars today easily last 3 to 4 times as long as 1950s cars did.