Men and women workers assembling Pratt & Whitney engine cylinder heads

View of men and women assembling cylinder heads for Pratt & Whitney engines. Label on back: "Picture 74878. Cylinder heads, Pratt & Whitney engine. 165 different operations are performed on these cylinder heads as they pass along this assembly line. They are removed from either side for machining operations which occur along the line. The line can be stopped at given points in order to accommodate the speed of various operations. The Greenlee Company is now building several huge multiple operating machines costing nearly $1,300,000 a piece which will virtually eliminate all of the separate operations taking place along this line." Handwritten on back: "Women workers."