shoulders through the Ford plant while others added the parts. Later life Sorensen was a major contributor to the launch of the Highland Park Ford Plant in 1910, where he was second in command to production chief Peter (Ed) Martin. He then helped with the development of the Fordson tractor and modernization of Edsel Ford's Lincoln when it was purchased by Ford from Henry M. Leland in 1922. Following transfer of auto assembly to the Rouge in the late 1920s, he was a "key leader" in manufacturing as number two man to Ed Martin, who was made vice president of manufacturing in 1924. He was manager of production planning and development. "Ed Martin, who was plant superintendent, and I practically lived at the Rouge." It has been said he considered himself the "Head of Production," and Henry Ford's "right-hand man," but he was only one of at least six company leaders claiming that distinction. (Ford's practice of telling his men to "[j]ust go out there and run the plant […] [a]nd don't worry about titles" contributed to these variations in viewpoints.) Sorensen's help in innovating foundry practice for mass production earned for him from Henry Ford the nickname of "Cast-Iron Charlie" during the company's first decade, when he invented (or at least independently reinvented) the use of metal patterns, instead of wood ones, to withstand the huge number of moldmaking cycles needed for mass production and methods of core registration to position the cores accurately without relying on the sand under them to assist in the registration. In 1928 Sorensen joined Henry and Edsel Ford as the three US directors out of seven on the board of Ford's new reorganized independent European operations. During the 1930s, Sorensen was also responsible for production techniques allowing the manufacture of a sophisticated V-8 engine block from a single casting, and using a more automated foundry workflow than ever before. The resulting Ford Flathead engine continued in production until 1953; a derivative design was used in French military vehicles into the 1990s. During the early 1940s, Sorensen had responsibility for Ford's defense contracts, including Ford's Jeep and aircraft engines and production of the B-24 Liberator bomber. He led the design of the Willow Run plant, where the B-24s were made, applying all of his previous experience in the development and refinement of mass production methods. Each was made up of 488,193 parts, and they