Public domain
Production. Pratt and Whitney airplane engines. Screws for valve rocker arms of Pratt and Whitney airplane engines are polished on a Gardner machine in a large Eastern plant. This operation is one of many high precision specifications which insure excellence of our fighting planes. Pratt and Whitney
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Credit lineProduction. Pratt and Whitney airplane engines. Screws for valve rocker arms of Pratt and Whitney airplane engines are polished on a Gardner machine in a large Eastern plant. This operation is one of . 1942-01-01. United States. Office Of War Information, Feininger, Andreas. Farm Security Administration/Office of War Information Collection, Library of Congress. Public domain.