“Numerical control as a concept developed in the mind of John Parsons as a way to produce integrally stiffened skins for aircraft, and this led to a series of Air Force research projects at the Massachusetts Institute of Technology, beginning in 1949.

“The initial planning-and-study phase was followed by the construction of an experimental milling machine at the Servomechanisms Laboratory at MIT. Prof J.F. Reintjes, director of the lab, James O. McDonough, Richard W. Lawrie, A.K. Susskind, and H.P. Grossimon were the people involved in the research.

“A 28-in. Cincinnati Hydro-Tel verticle-spindle contour milling machine was the starting point. It was extensively modified: all of the table, cross-slide, and head drives and controls were removed, and three variable-speed hydraulic transmissions were installed and connected to leadscrews. Each transmission would produce, through gearing and leadscrew, a 0.0005-in. motion of the table, head, or cross-slide for each electrical pulse received from the director. A feedback system was provided to make sure the machine was doing what it was told. A synchronous motor geared to each motion generated a voltage response to movement; this was sent back to the director and compared with the original command voltage.

“By 1951, the system had been assembled, and application studies were begun. By 1953, enough data had been assembled to indicate practical possibilities that could be developed. A detailed 24-page report on the process that appeared in American Machinist on Oct 25, 1954, started a flurry of further development. [...] But it was the initially more awkward, less accurate prototype at MIT, which employed a Flexowriter and its eight-column paper tape, a tape reader, and a vacuum-tube electronic control system that was to become the prototype for the developments that followed.”

http://www.cmsna.com/blog/2013/01/hi...cept-was-born/