Grain harvesting was revolutionized by Massey engineer Tom Carroll in 1938, with the world's first self-propelled combine — the No. 20. It was too heavy and expensive for extensive mass production, but served as a guide for the design of the lighter and less costly No. 21 which was tested in 1940, and put on sale in 1941. The Massey-Harris No. 21 Combine was commemorated with a Canada Post stamp on June 8, 1996. E.P. Taylor, one of C.D. Howe's dollar-a-year men, joined the board of directors in 1942, and Eric Phillips joined management in 1946.