Hey Frank, you might like this video... the gazelle factory in 1925, cranking out 3 speeds by the thousands. I really love the way they braze the frame, they just dunk it in a pool of brass and file away later! What amazes me the most is the way they produced all the bits and pieces (pedals, cranks...) on site, from bar, stock and plate, unthinkable nowadays.
http://www.geschiedenis24.nl/speler....m.7086772.html