It turns out, though, that among Leonardo’s inventions there is a whole
collection of proto-machine tools. For instance, around the year 1500, the
artist-turned-engineer sketched a lathe with a three-bearing head stock as well
as a screw cutting machine. Today's Machining World, April 2012
This fall I visited a Da Vinci exhibit in Denver, CO and looked at all of the great engineered items out of wood. I saw his gears, ball bearings, and beginnings of machines. He was a fore thinker and it is amazing to think it took so many centuries to develop the machines he initiated. http://www.davincithegenius.com/