A complex man, born July 30, 1863, Henry Ford developed the automotive mass production assembly line. His relentless and systematic focus on efficiency and costs reduction resulted in many technical and business innovations.
Between 1910 and 1916 total labor hours per car fell from over 400 to 130. The main labor savings were made by taking out indirect labor. In 1913 direct labor hours were 61 in a Model T, by 1916 direct labor hours were down to 37. The ratio of indirect to direct labor of 2.5:1. There's a correlation between stock levels and indirect labor; the more stock, the more material handling, counting, moving, managing.
The longer an article is in the process of manufacturing and the more it is moved about, the greater its ultimate cost. Henry Ford, 1926