Metal lathes for spinning Coolus helmets and such

[Medicus matt]

On the control/regulation issue, I have a dim mental picture of a wide leather strap clutch around a flat wheel, but I couldn't describe it better. Essentially, iirc, an operator puts more or less tension on the drive wheel by tightening the strap with a lever to produce more or less speed. I can't recall where I saw that mechanism, so I can't be more specific.

I don't think they built complicated pulley mechanisms, though, like you'd see on top of a multi-speed drill press, for example. And we don't find a lot of gearboxes, either, so it would have had to be something more direct and simple than that.

Gears, friction and toothed are described by classical writers but only in relation to clever gadgets like Archimedes' mechanical plantarium, not industrial processes.

I've got a dim recollection of a mention of some sort of gearing being used to lathe -turn the drums for stone columns but can't remember where it was.