The Amalgamated Society of Brassworkers was formed in 1872. It changed its name to the National Society of Amalgamated Brassworkers in 1873, the National Society of Amalgamated Brassworkers and Metal Mechanics in 1905, the National Society of Brassworkers and Metal Mechanics in 1911, the National Society of Brass and Metal Mechanics in 1920, and the National Society of Metal Mechanics in 1944. It merged with the Technical, Administrative and Supervisory Section (TASS) in 1987.
The National Society of Amalgamated Metal, Wire and Tube Workers may have been formed by the National Society of Metal Mechanics in an attempt to cater for a different (and possibly less skilled) type of metal worker. The two organisations shared the same General Secretary and offices.
Reference: M. Totten, Founded in Brass (National Society of Metal Mechanics, 1972).