Louis Polk (1904-1991)
Polk’s association with City Machine & Tool Works in Dayton began as a messenger boy. He returned to the firm as a designer after graduating from the University of Miami in Ohio in 1926. Five years later he was general manager and in 1941 merged the company with Sheffield Machine & Tool, becoming president of the resulting Sheffield Corp. He is best known for the development of the column-type Precisionaire dimensional comparator. These gages played an important role in airplane production during World War II. Later they were widely applied to machine tools, providing a method of in-process gaging on a variety of machines. Sheffield concentrated on developing a variety of gages and measuring systems and a line of grinders using an in-process optical comparator to obtain precision. After Sheffield was acquired by Bendix in 1956, he continued to head the firm until 1963. Long active in standards development, he was a delegate to the 1960 conference that replaced the meter bar with an isotopic wavelength of light, served on many standards boards and committees, often as chairman, and was chairman of the U. S. Metric Advisory committee.