Can anyone give me a patent or general introduction date for Phillips head
screws/screw drivers? A friend of mine saw them used in a reconstruction
of the launching track at Kitty Hawk, and thinks they should post-date the
Wrights' being there, 1900-1905. I said I thought they came in around
World War II, but that's a guess, and I like it less, the more I think
about it.