December 10
First sit-down strike in U.S. called by IWW at General Electric in Schenectady, N.Y. - 1906
December 10, 1915 - On this day, a Model T rolled off the Ford assembly line, reaching the 1 million mark in production. Ford's innovative assembly line made it easier and cheaper to manufacture cars and made workers just one more cog in the machinery of production. Twenty years later, workers at Ford plants would form unions to improve their lot.

International Human Rights Day, commemorating the signing at the United Nations of the Universal Declaration of Human Rights, which states, in part: “Everyone has the right to form and join trade unions for the protection of his interests” - 1948
American Federation of Teachers Local 89 in Atlanta, Georgia disaffiliates from the national union because of an AFT directive that all its locals integrate. A year later, the AFT expelled all locals that refused to do so - 1956
Labor history found here:
http://www.unionist.com/today-in-labor-history & here:
http://www.workdayminnesota.org/index.php?history_9_12_10_2010