Pretty certain he simply meant "machined like clockwork", which are the gears and springs that power mechanical watches and clocks. AKA "Built like a Swiss watch", with exacting precision details and very fine tolerances. Even though the machine is gigantic, the tolerances in bearings and surface, while maybe not actually quite as precise as a watch, are indeed very small, especially when compared to the overall size of the machine.

Ah, I see like I said I don't know much about machining. I am wishing to know more so I tend to ask questions.....Sometimes dumb ones. But who hasn't!

Steam locomotives are very tolerant, but smooth needs to be smooth, even if not quite round. Journals can be scored around the circumference, but if across the bearing laterally, it disrupts the lubrication film causing a lot of heat and trouble. Crankpins get pitted, and an old friend in the Pacific Northwest relies on the pits to help carry the hard grease around the bearing - or so he says.

dave