The union was founded in 1839 as the London Printing Machine Managers' Trade Society.
Steam-powered printing machines were being gradually introduced to the trade, and its members differentiated themselves from the compositors who held membership of existing societies.
[1] The union focused on matters directly relating to the industry, and did not pay benefits to members who were out of work.
To cover this, it set up a related organisation, the "Machine Managers' Benefit Society".
[1][2] It finally agreed a working arrangement with the London Society of Compositors in 1953, and merged into that union two years later.