Lathe
Lathes represent one of the earliest machine tool families and were probably in use as early as 700 B.C. The invention of the cord drive for the rocking drill--the first mechanical cutting tool--made possible a similar drive system for the lathe, which in its simplest form is a tool used to support and rotate any material for the purpose of shaping by a cutting instrument. The many lathes that followed the ancient Etruscan, Egyptian, Syrian, and Greek rotary lathes made advances in at least one of three areas: 1) increased rigidity of the lathe spindle or axis; 2) increased power and efficiency of the drive mechanism; 3) progressive elimination of hand operations.
First came the pole lathe, around the twelfth century. The distinctive feature of this machine was a foot-operated treadle attached to a spring pole to drive the lathe spindle. The pole lathe was a significant improvement because it allowed for easy single-person use. However, it was considered ill-suited for cutting metal because the drive system could not be sustained indefinitely.
To solve this problem, the continuous band method (which relied on a combination of a large wheel and such power sources as water, horse teams, and, later, steam engines and electric motors) was invented in the fifteenth century. In addition to providing a reliable rotation system, the continuous band method made possible innovations in the actual cutting process, including tool holders and cross slides for enhanced precision.
The most significant developments in lathe manufacture occurred after a gradual conversion to all-metal components, which began around the mid-eighteenth century. The oldest all-metal lathe, circa 1751, was that built by Jacques de Vaucanson (1709-1782), for use in his loom machines. The Vaucanson lathe is also credited as being the first slide lathe, used expressly for cylindrical turning of metal pieces and characterized by prismatic slide bars.
In 1797 Englishman Henry Maudslay built a screw-cutting engine lathe. Precision screws had been cut by clockmakers on lathes since the late 1400s, but Maudslay's machine represented an enormous advance because of his introduction of the lead screw, geared to the lathe spindle. This lead screw allowed for controlled advancement of the cutting tool, and thus ensured the rapid machining of precision screws. By adding gears and altering the lead screw speed ratio, Maudslay was able, by the end of the century, to cut a variety of thread pitches with a single machine. For his contributions, Maudslay is regarded as the father of the industrial lathe.
During the same period, an American named David Wilkinson (1771-1852) developed a similar screw-cutting lathe that may have been based on drawings by Leonardo da Vinci. Wilkinson eventually produced a large general purpose lathe in 1806 that became the foundation of the American machine tool industry. Another American, Thomas Blanchard, first developed a lathe for producing non-symmetrical forms, such as gunstocks, and then, around 1818, a lathe that made use of a friction wheel to duplicate any of a large number of original patterns. Blanchard's machine, like Wilkinson's, was central to the development of modern manufacturing processes.
Lathe innovations, many of which related to increasing spindle speed and refining measurement accuracy, continued well into the twentieth century. Today the lathe, given its wide adaptability to automated production, is still regarded as the most widely used and most important machine tool. Shapers, planers, drilling machines, milling machines, grinding machines, and a number of other important industrial inventions all trace their existence to the original machine tool, the lathe.
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