I have lost all of my old magazine articles that dealt with the early implementation of NC machines.
But from memory, I thought that it was McDonald Douglas (spell) in the aerospace industry that first used NC machines in the 60's. They were controlled from punch cards and later on from punched tape.
Interestingly, they are NC, not CNC as they didn't use a computer at that time. In the early 80's I used to program a NC turret press by typing in G code on a typewriter style machine. It would punch out the tape and type my code at the same time. We would write the programs out long hand and then type them out. Very error prone. Programs were very rarely correct on the 1st try.
I am also pretty sure that some of the commercial CNC router companies have this historical data. Try
www.thermwood.com for example. They claim to be one of the first CNC router companies, so I am sure that they would some back up information.
Good luck on your search. Your work is very inspirational.
Trent