If you were working in a factory during the mid-1800s, would you be a striker or a strikebreaker?
Probably a strike breaker.
If you consider the mid-1800s to be roughly from 1835 to 1870 then as a factory worker you probably did not experience a strike.
The first unions to appear in the United States involving factory workers was the Knights of Labor but their first year as a union was 1870. From the beginning they were a very popular though fairly weak union and were eventually displaced by the American Federation of Labor.
That means that during the mid-1800s labor was not organized where factories were concerned.
Most strikes that did occur were among the skilled tradesmen, the mechanics union in particular. One of those prone to striking were the typographers.
The thing is, relative to the question asked, if a group of workers in a factory went on strike they were simply replaced by those in need of work, or as you call them, strikebreakers. This practice actually continued into the 20th century when the great strike of textile workers in Lawrence Massachusetts in 1912 changed that.