Here in CT, there was a precision tool shop called Moore Special Tool in Bridgeport. They used to make the industry standard measuring devices and tools. There was a room of flat stone tables that were used constantly for measuring purposes. The most skilled guys there would hand lap the stones every so often (on a schedule) to keep them in true. As I recall, the lapping process was all done by hand. Reference stones were used to monitor progress and validate. These stone tables were quite large.
There were some Moore tools that lived inside of
oil filled plastic mist boxes, perhaps 10 feet by 10 feet. These tools would be used for ultra critical measurements and milling and the
oil mist would maintain the environment with a rather sophisticated cooling and heating sub-system. You could think of it as a Bridgeport inside a glass box. BTW, speaking of Bridgeport, they were one of Moore's largest and perhaps closest customers.