In the beginning, automobiles were built by craftsmen who assembled the finished vehicle from parts they themselves had made, making any necessary adjustments to these parts as they went along. On the road to mass production, many improvements were made that speeded up the process and optimized the use of skilled labor.
The quality and uniformity of interchangeable engine parts was standardized. The use of machine tools and templates in parts production was introduced, permitting the use of less skilled workers and separating that contribution from the main assembly operation. Ford minimized labor turnover and ensured an eventual market for his cars with introduction of generous wages and hours for workers who matched his requirements.
Companies that specialized in manufacturing only certain parts grew, giving further meaning to the assembly process which now spread to include a variety of specialty suppliers. The first assembly line for mass production of automobiles was set up by Ransom E. Olds for the Olds Motor Works in 1901. Six hundred models of his Curved Dash Oldsmobile were sold in that year, rising to five thousand in 1904.