Hi guys.
Well this thread is a cry for a history lesson. My questions are concerned with the technology that existed in the beginning of the XX century, specifically how were metal stamping dies (you know, to make car doors/hoods/fenders) made?

Back then there were no computers, no CAD/CAM programs to help us, so how did they carve the molds of the fenders of, say, Ford Model A?
I can imagine them using tools to machine said dies by hand, but how did they make sure the dies were up to the designer specs? With careful machining? And how, after machining a die for the left fender, did they make sure they created the die for the right fender as a perfect symmetrical? Was there any jig? Was it once again done by somebody with steady hands and a remarkable attention to detail?

If you guys have some information or you know the title of old books on the subject, even some old photos will make me thank you a lot. I find this type of history extremely fascinating.