Women in war. Machine gun production operators. This capable young woman is making an important contribution to America's war effort. Employed by a Midwest plant, converted from the production of spark plugs to machine guns, she's one of many skilled women milling-machine operators who are producing weapons for America's armed forces. Here, she's checking a slot she has just milled in a gun part. A.C. Spark Plugs. Sourced from the Library of Congress.