Editing Mass production (section)

=== Factory electrification ===
[[Electrification]] of factories began very gradually in the 1890s after the introduction of a practical [[DC motor]] by [[Frank J. Sprague]] and accelerated after the [[AC motor]] was developed by [[Galileo Ferraris]], [[Nikola Tesla]] and [[Westinghouse Electric (1886)|Westinghouse]], [[Mikhail Dolivo-Dobrovolsky]] and others. Electrification of factories was fastest between 1900 and 1930, aided by the establishment of electric utilities with central stations and the lowering of electricity prices from 1914 to 1917.<ref name="Jerome 1934">{{cite book |last=Jerome |first=Harry |title=Mechanization in Industry |publisher=National Bureau of Economic Research |year=1934 |page=xxviii}}</ref>

Electric motors were several times more efficient than small steam engines because central station generation were more efficient than small steam engines and because [[line shaft]]s and belts had high friction losses.<ref>{{cite journal |last=Devine |first=Warren D. Jr. |title=From Shafts to Wires: Historical Perspective on Electrification, Journal of Economic History, Vol. 43, Issue 2 |url=http://www.j-bradford-delong.net/teaching_folder/Econ_210c_spring_2002/Readings/Devine.pdf |url-status=dead |page=355 |year=1983 |access-date=3 July 2011 |archive-url=https://web.archive.org/web/20190412093317/http://www.j-bradford-delong.net/teaching_folder/Econ_210c_spring_2002/Readings/Devine.pdf |archive-date=12 April 2019}}</ref><ref>{{cite book |title=Creating the Twentieth Century: Technical Innovations of 1867-1914 and Their Lasting Impact |last=Smil |first=Vaclav |year=2005 |publisher=[[Oxford University Press]] |location=Oxford / New York City |url=https://archive.org/details/creatingtwentiet0000smil|url-access=registration}}</ref> Electric motors also allowed more flexibility in manufacturing and required less maintenance than line shafts and belts. Many factories saw a 30% increase in output simply from changing over to electric motors.

Electrification enabled modern mass production, as with Thomas Edison's iron ore processing plant (about 1893) that could process 20,000 tons of ore per day with two shifts, each of five men. At that time it was still common to handle bulk materials with shovels, wheelbarrows and small narrow-gauge rail cars, and for comparison, a canal digger in previous decades typically handled five tons per 12-hour day.

The biggest impact of early mass production was in manufacturing everyday items, such as at the [[Ball Brothers]] [[Ball Corporation|Glass Manufacturing Company]], which electrified its [[mason jar]] plant in [[Muncie, Indiana]], U.S., around 1900. The new automated process used glass-blowing machines to replace 210 craftsman glass blowers and helpers. A small electric truck was used to handle 150 dozen bottles at a time where previously a hand truck would carry six dozen. Electric mixers replaced men with shovels handling sand and other ingredients that were fed into the glass furnace. An electric overhead crane replaced 36 [[day labor]]ers for moving heavy loads across the factory.<ref>{{cite book |last=Nye |first=David E. |title=Electrifying America: Social Meanings of a New Technology |publisher=[[MIT Press]] |location=Cambridge, MA / London |year=1990 |pages=14, 15}}</ref>

According to [[Henry Ford]]:<ref>{{cite book |title=Edison as I Know Him |last1=Ford |first1=Henry |author1-link=Henry Ford |last2=Crowther |first2=Samuel |year=1930 |publisher=Cosmopolitan Book Company |location=New York |page=15 (on line edition) |url=http://quod.lib.umich.edu/g/genpub/3936620.0001.001?view=toc |access-date=7 June 2014 |archive-date=17 July 2014 |archive-url=https://web.archive.org/web/20140717204915/http://quod.lib.umich.edu/g/genpub/3936620.0001.001?view=toc |url-status=live}}</ref>
<blockquote>The provision of a whole new system of electric generation emancipated industry from the leather belt and [[line shaft]], for it eventually became possible to provide each tool with its own electric motor. This may seem only a detail of minor importance. In fact, modern industry could not be carried out with the belt and line shaft for a number of reasons. The motor enabled machinery to be arranged in the order of the work, and that alone has probably doubled the efficiency of industry, for it has cut out a tremendous amount of useless handling and hauling. The belt and [[line shaft]] were also tremendously wasteful – so wasteful indeed that no factory could be really large, for even the longest line shaft was small according to modern requirements. Also high speed tools were impossible under the old conditions – neither the pulleys nor the belts could stand modern speeds. Without high speed tools and the finer steels which they brought about, there could be nothing of what we call modern industry.</blockquote>
[[File:Airacobra P39 Assembly LOC 02902u.jpg|thumb|The assembly plant of the Bell Aircraft Corporation in 1944. Note parts of [[overhead crane]] at both sides of photo near top.]]

Mass production was popularized in the late 1910s and 1920s by Henry Ford's [[Ford Motor Company]],<ref>{{Harvnb|Hounshell|1984|}}</ref> which introduced electric motors to the then-well-known technique of chain or sequential production. Ford also bought or designed and built special purpose machine tools and fixtures such as multiple spindle [[Drill#Drill press|drill presses]] that could drill every hole on one side of an engine block in one operation and a multiple head [[milling machine]] that could simultaneously machine 15 engine blocks held on a single fixture. All of these machine tools were arranged systematically in the production flow and some had special carriages for rolling heavy items into machining position. Production of the [[Ford Model T]] used 32,000 machine tools.<ref name= "Hounshell1984p288">{{Harvnb|Hounshell|1984|p=288}}</ref>