From Home To The Factory
Home Production
Before the American Indsutrial Revolution, all products were hand made by individuals who specialized in a specific type of work, such as shoemaking. Even during the first few years of the Revolution, before factories, individual parts for a whole product were made in different homes to be put together somewhere else. This way, many goods were expensive and to get a job, you either had to specialize in the production of an entire product, or piece of a product. Also, each product would be different from another, not allowing for replacement parts to be purchased for repairs.
Factory Production
Over time in the early-mid 1800's, factory life started to dominate the old home production systems. Rather then have one man specialize in the making of one product, machines would do the work, allowing for anyone to get a job. This also allowed for interchangeable parts, the product of an assembly line. This was first seen with Eli Whitney's production of 10,ooo muskets for the United States armoury, where each musket was created in an assembly line and each piece on one firearm would match that on another. These innovations in industry are what led to today's type of production, meaning cheap and similar products made by machines.
("The Factory System Emerges: 1733–1865")