At the end of December 1870, they held their first congress in which a regulation was approved with the guidelines of the Spanish Regional Federation of the IWA (FRE-AIT).
One of the most important struggles of this period, promoted by the Three Classes Federation, was the fifteen-week strike in Villanueva y Geltrú, which affected 1,400 workers.
[3] On February 4 and 5, 1872, they held their second congress, where they unanimously approved the regulation of strikes and the federation with the Society of Weavers by hand, to form the Union of Manufacturing Workers.
This trend caused the split of the Manufacturing Union in March 1882 when it joined the Federation of Workers of the Spanish Region (FTRE), with Josep Bragulat as general representative.
The protest strike that was decreed, almost unexpectedly, was supported not only by the sections of the Three Steam Classes but also by those of cotton, palettes, locksmiths, dyers, carpenters and shoemakers.
In 1909, at an assembly of the Federation of the Art Industry of Catalonia in Barcelona, representatives of the Three Steam Classes of Torelló, Sant Martí de Provencals, Badalona and Manresa attended, without a clear relationship between them.