Would probably need a large engine to power it as well, with careful control because the resisting force would vary along the machine cycles (this could be used as a side channel attack vector to figure out internal state from resisting force).
The control box was a convenience and made the process fully programmable by the user. Which makes the machine far more flexible and useful.
I call it analog randomness because that's what I expect from the real world. For thousands of years, humans have used coins and dice to generate uncertain outcomes. And the fact that they typically generate only one of N outcomes (N=2 for coins, N=6 for common dice) is why humans use them. It is also why the Satoshi9000 uses them, and because its a kind of randomness that humans have an intuitive recognition of.
Now I'm thinking of a random number generator that uses a mechanical calculator printer (but I don't think there are any hex-capable ones easily available) or a typewriter to write password suggestions. The mechanical part would be tricky, because the hammers require some force to be actuated (and I would find it criminal to destroy a vintage typewriter for that).