Every new car starts as a drawing. Designers make big clay models of a new car. They cut and shape the clay by hand.

Cars are built in very big factories. A BMW plant in South Carolina builds more than 1,500 vehicles every day. A car is made of thousands of parts, and people and machines put them together.

Body parts are made from big rolls of steel or aluminum. The rolls are cut into flat pieces. Big presses squeeze them into the shapes of doors and side panels. A press line can press up to 18 times a minute.

Tesla casts parts a different way. It uses giant machines to cast big parts of a car body from molten aluminum in one piece. Tesla calls its giant casting machine a Giga Press.

A car's paint is put on in layers, not all at once. Primer makes the surface smooth and even. A base coat gives the car its color. The Ford Model T was not always black. Early Model Ts came in colors such as red, green, blue and gray.

A clear coat goes on top. It protects the color from sunlight and from air that can dull it.

Karl Benz applied for a patent on 29 January 1886 for his motor vehicle. The patent paper is now called the automobile's birth certificate. His car could go only about 10 miles per hour at best, and it was one of the very first cars. Bertha Benz took one of her husband's cars on the first long-distance journey in car history, without telling him first.

Ford was not the first carmaker to use an assembly line. Ransom Olds built cars on an assembly line before Ford did. Olds's was a still assembly line. He sold his small Curved Dash car for $650 in 1901.

What was new in 1913 was a line that moved the car to the workers. Ford's line first ran at his Highland Park plant in Michigan in October 1913. Before it, workers built each car by hand while it stayed in one place.

Ford first tried the line on a small part. A magneto took 20 minutes to build, and after the line it took five. Then the Model T line kept getting faster. At first it cut the build time from 12.5 hours to under 6. Within a year it took 93 minutes. A new Model T cost $850 when it first came out. Later the price fell to $260, so many more families could buy one. About 15 million Model Ts were built before the car was dropped in 1927.

Words to know

• patent: invention paper
• primer: first coat
• cast: pour metal
• magneto: spark maker

The short version

Cars are built in big factories from thousands of parts. Ford did not invent the assembly line. Ransom Olds used one first. What was new in 1913 was a line that moved the car to the workers, which cut the time to build a Model T from 12.5 hours to 93 minutes within a year.

Quick facts

• A BMW plant in South Carolina builds more than 1,500 vehicles every day.
• Ford's 1913 line moved the car to the workers. Ransom Olds had used a still assembly line before.
• Ford's Model T build time fell from 12.5 hours to 93 minutes within a year.
• About 15 million Model Ts were built before the car was dropped in 1927.
• Car paint is put on in layers: primer, a base coat and a clear coat.