I think the very worst way to recruit factory workers was from the orphanages and workhouses. Sometimes the children were as young as six years old, very poorly fed and clothed, overworked, and exposed to very dangerous conditions. Many died. These horrific conditions eventually led to child labor laws prohibiting children under the age of 14 to work.
A second way to recruit factory workers was to entice them into newly formed trade unions. They were promised better wages, living conditions, and better jobs. Especially targeted were the massive waves of immigrants coming to America for a better way of life. They were recruited by the thousands.
A third way to recruit factory workers was to appeal to the womenfolk. With automation and machines taking away some of the tasks they used to do by hand, they were freer to go into the job market. Men used propoganda to convince the women they were strong, intelligent, and very needed.
Life must have been extremely hard, cheerless, and depressing during this period of history. In fact, there have been several historians who've argued over the benefits versus the disadvantages of our country going from an agricultural society to city life overnight. Was it really worth it?