boring mill, machine tool used to increase the size of a hole previously made in a workpiece, usually with the purpose of obtaining a required degree of finish and accuracy in the final hole. In a horizontal boring mill the workpiece is held stationary on a vertical table whose position can be adjusted. A spindle attached to a vertically adjustable head holds the cutting tool, which is fed horizontally into the work. In a vertical boring mill the workpiece is made to revolve on a horizontal circular table as the tool is fed in.

Boring, Edwin Garrigues, 1886-1968, American psychologist, b. Philadephia. He taught experimental psychology at Clark Univ. (from 1919) and at Harvard (1922-68). Boring was strongly influenced by Edward Titchener and is best known for his work in sensory psychology. Boring's classic History of Experimental Psychology (1929) made him a pioneer historian of the field. Other important works include Physical Dimensions of Consciousness (1933), and his memoirs, Psychologist at Large (1961).

Machine tool for producing smooth and accurate holes in a workpiece by enlarging existing holes with a cutting tool, which may bear a single tip of steel, cemented carbide, or diamond or may be a small grinding wheel. The hole's diameter is controlled by adjusting the boring head. Bored holes are more accurate in roundness, concentricity, and parallelism than drilled holes. Boring machines used in toolmaking shops have a vertical spindle and a work-holding table that moves horizontally in two perpendicular directions so that holes can be accurately spaced. In mass-production plants, boring machines with multiple spindles are common. Seealso drill; drill press; lathe.

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