Man's physical universe



Industrial Accidents Have Declined.

As the result of the development of a vast number of safety devices

and other improvements industrial accidents have been reduced 61 per

cent in frequency and 61.3 per cent in disabling injuries.

Highly mechanized industries have the best safety records.

Machine Tools Have Played an Important Part in the Advance of Technology.

Watchmaker's precision,

precision to a ten-thousandth of an inch,

has been made possible by modern machine tools, which represent a

major contribution of engineering, metallurgy, and invention to modern

civilization. Machine tools are the reproductive members of the machine

world. Machine tools are the machines that make machines.

Fig. 106. A milling machine simultaneously finishing both sides of a large

Diesel engine connecting rod. The two cutters have multiple teeth, similar to a

circular saw. One of them is seen at the small end of the rod; the other is just

behind it.

The connecting rod is passed back and forth between the cutters which are

rotated at high speed and moved closer and closer together with each pass until

the rod is reduced to the desired thickness. (Courtesy of the National Machine

Tool Builders' Association.)

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