Saw this today about the swastika. Thought I should share it here since Jimmy had brought the subject up recently.
In reference to the pre- dynastic precision stone vases, these cutters are all set to the same length so they can all run together on a machine with multiple cutting heads. This is about as close as you get in the aircraft industry. These are all within .0002" or about 7 microns. The parts these cutters make are held to a tolerance of +.005 -.003 inches.