The American Federation of Labor is composed of national and international unions, which are organized on craft lines, such as carpenters or machinists. The machinists' local union belongs to the machinists' international union, and the carpenters local to the carpenters' international union. The American Federation not only co-ordinates the work of the national and international unions on the national level, but it also effects cooperation at the state and local levels through state federations of labor and central labor unions.
Local unions may form associations with other local unions of different crafts within a given area. These local associations are called central labor unions, which receive their charters from the American Federation of Labor. Local unions and central unions may also affiliate with state-wide organizations called state federations of labor. These state federations also receive their charters from the American Federation of Labor.
This system is not a chain of command. Correspondence may flow directly between the organizations without intermediate consideration, or there may be parallel correspondence of a local with the state and national federations. Each union carries on its own inter-union correspondence, as well as exchanges with outside parties.
