A great man

I am particularly fond of your recent regular feature about Nikola Tesla (whom I “discovered” while in college and who impressed me to no end). I read all the previous installments on your website. Bravo on those articles.
Jeff Knoedler
Hydraulic Engineer
Vactor Manufacturing Inc., a division of Federal Signal Corp.
Streator, Ill.

Looking back

I have a question about the photo shown on page 51 in your April 2006 issue, which is referred to as a CNC machine in 1948. It looks like a knee and column mill, vertical universal, with a motor-driven dividing head mounted on the table. I believe CNC came out in the 1970s.

In 1961 I worked for Cincinnati Milling and Grinding Machine Co., then the largest machine tool builder in the world. We referred to our “advanced” machines as Numerically Controlled, meaning information for slide movement was given in numbers. In the 1960s the industry started talking about using a computer to control machines. A Numerically Controlled (NC) machine used punched cards, punched tape, or dials to tell the NC control what to do. As computers became smaller and more powerful, we used one that controlled the machine with software, not hard-wired devices. That's when we began using the term CNC, or computer numerical control. During the 1960s, we went from hard-wired NC to software controlled NC and called it CNC.

I'm not saying there wasn't a computer controlling four axes back in 1948, but I'm not sure how practical it would have been, considering it was probably much bigger than the machine tool. The growth of this technology from the late 1950s to now, from vacuum tubes to solid state, and now to integrated circuits has helped numerically controlled machines evolve.

I look forward to reading about the history of CNC in future articles. I'm sure it will fill in some of the gaps that the “Mill” neglected to tell us “young” apprentices back in 1961.
Doug Moore
Manager Education Programs
Kennametal Knowledge Center

The book Forces of Production chronicles the development of CNC machining and dates its origins to the 1940s. However, you're right. The mentioned photo is not of a CNC machine, but a precursor.