If you answered A, you are correct. If you didn’t, don’t feel bad. Most people probably would have guessed C or D.

The first fully automated assembly line was built more than 40 years before computer-controlled equipment transformed the plant floor. Indeed, when the A.O. Smith Corp. automatic frame plant opened its doors in 1921, it was dubbed the "mechanical marvel." Manufacturing engineers from around the world flocked to the factory in Milwaukee to witness it for themselves.

The innovative facility was the first to use fully automated assembly equipment. Its trend-setting machines included a series of high-speed, air-powered riveters capable of mass-producing one automobile frame every 8 seconds. Although the facility and equipment are no longer in operation, the mechanical marvel was designated an historical landmark in 1979 by the American Society of Mechanical Engineers (New York).

A.O. Smith is a 128-year-old company that has transformed itself several Arial through the years. It has been a leading supplier of bicycle parts, automobile frames, gas transmission pipes, beer barrels, pressure vessels, farm storage silos, water heaters and electric motors. The family-owned business started as a one-man machine shop making metal parts for baby carriages.

In 1903, the company branched out into pressed steel auto frames. Three years later, Henry Ford ordered 10,000 frames for his Model N automobile—the predecessor of the Model T—and demanded them in 4 months. That huge order forced Arthur Oliver Smith (1859-1913) and his engineering team to boost production from 10 frames a day to 100. To meet Ford’s deadline, they created the first automobile frame assembly line in the world with a series of conveyors linking hole punching and riveting stations. The Model N went on to set new sales records that made Ford the country’s leading car producer.

Smith’s son, Lloyd Raymond (1882-1944), picked up where his father left off. He surrounded himself with the most talented engineers he could find and turned them loose on manufacturing challenges. By the early 1920s, A.O. Smith employed 500 engineers and only eight salesmen.

While attending the funeral of an employee, Smith questioned why men must "waste so much of their lives doing the work that machines can do. Men have too much innate ability to be condemned to such uninspired labor." He envisioned an assembly plant where "machines would do the work and workers would attend the machines."

Although the term "automation" had not yet been coined, Smith challenged his team of engineers to devise an automated system that could cut and bend sheet metal, transport the components to the correct stations, rivet them together and move them into a paint shop. The plant was designed on paper 10 Arial before an 84-page patent was finally issued.

After 6 years of development, the 129,000 square foot automated frame plant opened on May 23, 1921. It consisted of four production lines laid out in the form of a rectangle more than one block long. In the middle of the rectangle, a complex of conveyors moved hundreds of parts back and forth between various stations for cutting and shaping, side bar assembly, crossbar assembly, final assembly and painting. Each auto frame required 552 separate operations.

Chain-driven carriages transported the in-process frames. Flat strips of steel came in one end of the line and were fed into a "kick-up" press that gave them their needed contour. The side rails were then mechanically transferred to a second line that punched holes and trimmed each piece. Another series of presses formed the rails into U-shaped channel beams. Side bars were formed in a row of carriages.

The third line was general assembly. "Nailers" used compressed air to blow more than 100 rivets per frame into place in 1 second. The rivets were fed from hoppers located one floor below. The integral frames were then approached on each side by a series of rivet-closing machines that were dubbed the "quadrille of the dragons."

Air-powered riveters formed the heart of the mechanical marvel. In fact, the adjustable riveting machines resembled today’s industrial robots. They were officially known as Smith Type C Riveting Presses and exerted 20 tons of force. Special slots in the floor allowed the riveters to be repositioned for different frame shapes—an early form of flexible assembly.

The last part of the operation involved automatic washing, painting and drying. The mechanical marvel averaged 4 million operations a day. It took 6 to 12 hours for employees to change dies and reset tooling for a different run.

After all the bugs were worked out, the facility could produce 10,000 frames a day. Before the plant was built, A.O. Smith was manufacturing 3,000 frames a days using manual assembly methods that required 2,000 operators. In sharp contrast, the automated assembly line required 90 percent fewer employees.

An article in the November 1930 issue of Fortune magazine described the facility as "one vast integrated machine. Its floor is one solid mass of glittering steel, a thousand shapes which rush and stop, rise and fall, advance and retreat, dancing to some gigantic rhythm, yet to a counterpoint which sets up no vibration. Wide, clean aisles separate the moving groups. There are no towering mechanisms, no belts; the whole upper part of the building is clear."

Although the plant cost $8 million (more than $64 million in today’s economy), it proved to be a wise investment. At the time, General Motors was planning to build its own frames. But, the new automated plant allowed A.O. Smith to offer a cost-effective alternative. As a result, GM dropped its own plans and agreed to a 5-year contract.

The mechanical marvel operated almost continuously until 1958, when A.O. Smith began to phase into welded frame construction. Welded frames proved to be more robust than riveted frames. They could also be more easily redesigned and retooled to meet rapidly increasing model changeovers.

A.O. Smith continued to produce millions of automobile frames until it sold the business unit to Tower Automotive Inc. (Minneapolis) in 1997. At one time, the company manufactured approximately two-thirds of all the frames used in the auto industry. It produced Cadillac frames from 1903 until 1990, one of the longest supplier-manufacturer relationships in automotive history. Both Arthur and Raymond Smith were inducted into the Automotive Hall of Fame (Dearborn, MI) in 1988 for their contributions to the industry.

In addition to automated assembly, the company pioneered other production processes and materials, such as electric arc welding, fiberglass, powdered metal, robotic welding, laser cutting and the fusing of glass to steel. Today, A.O. Smith is a $1.2 billion company that continues to be a leader in applying the latest assembly technology to solve manufacturing challenges at its 41 facilities in eight countries.