The History of Interchangeable Parts in the Industrial Revolution

Interchangeable parts brought about rapid industrial development, but the event that brought about their popularity was actually a lie.
Trevor English
Bell Aircraft assembly plant.United States Library of Congress/Wikimedia

The industrial revolution thoroughly changed the world. It turned economies upside down and reinvented how society gets by. One of the most important, perhaps the most prominent, of inventions to come out of the industrial revolution was the idea of interchangeable parts.

Prior to the industrial revolution, there was no standard for creating machine parts. That meant that every machine was essentially its own custom design that was built in a "one-off" production style. This obviously meant that replicating machines to enhance their spread across the world was quite hard.

Eli Whitney's demonstration

In 1801, a man by the name of Eli Whitney pioneered a new manufacturing method. He had successfully demonstrated the concept of interchangeable parts. 

First conceptualized by French General Jean-Baptiste Vaquette de Gribeauval in the mid-18th century, the idea had been around for some time. Gribeauval even started producing firearms with interchangeable flintlocks in 1778. However, the idea never really made it much further than that.

The idea was simple, if individual pieces of a machine were produced identically, then the final product would be identical to others. This would also allow for easy fixing of broken parts, allowing machine owners to simply order a replacement. 

The first testing ground for interchangeable parts by Whitney was demonstrated within firearm production.


Whitney took 10 of his interchangeable rifles before congress. While standing in front of the crowd, he disassembled all of them, mixed up al of the parts, and then reassembled them in working order. This would've been incredible at the time as everything prior was custom made.

The History of Interchangeable Parts in the Industrial Revolution
Source: Internet Archive Book Image/Flickr

It was at this moment that the idea of interchangeable parts started to take hold of the entire industrial revolution.

Ironically, Whitney's demonstration was all a lie. 

Whitney's contract for guns

In 1797, the U.S. Congress voted to prepare to go to war with France. First, they needed to order a massive amount of weapons. 

At this time, Eli Whitney was already well known for his invention of the cotton gin and played off of this to win a contract for 10,000 muskets from the government. By 1801, Whitney hadn't produced and delivered a single weapon to the government and was thus called to congress to justify his use of funds in front of John Adams and Thomas Jefferson.

Whitney came prepared though with his 10 "interchangeable rifles". He put on the demonstration we mentioned before, but it was all a lie. Whitney had marked the parts prior to the demonstration so that he could reassemble them correctly. Nothing was interchangeable – but Congress didn't know that.

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The demonstration by Whitney earned him major federal support at the time and his efforts were no longer in question. While the display might've been fake at the time, the idea wasn't.

Whitney eventually delivered the last of his 10,000 muskets 8 years later and due to their quality, he was ordered to produce another 15,000 over the next four years.

Historians actually believe that Whitney never actually achieved the process of interchangeable parts in his lifetime, but rather his Gun Manufacturing Company was able to after his death.

Other efforts to create interchangeable parts

While Eli Whitney's highly public displays pushed interchangeable parts to the forefront of industrial culture, he wasn't able to achieve major success in this realm. 

In 1803, Marc Brunel, famous engineer, along with the help of others was first able to mass-produce interchangeable parts. He streamlined a process of creating pulley blocks for naval shipyards using metal machines and a crew of only 10 men. These pulleys were made of wood and demonstrated that interchangeable parts were achievable on a large scale. 

The History of Interchangeable Parts in the Industrial Revolution
Brunel's interchangeable pulley blocks. Source: GK Bloemsma/Wikimedia

By 1816, a man by the name of Simeon North had created the world's first metal milling machine. This machine allowed manufacturers to create parts with tight tolerances, which would've been a key aspect needed to create metal interchangeable parts on a large scale. 

Historians now believe that at some point prior to 1832, North was able to create metal interchangeable parts using his milling machine. The process would have involved a rough-forged original part that would've then been milled down to exact specifications.

By the mid-1800s the concept of interchangeable parts was spreading across the entire world of manufacturing. Surprisingly, it would take another century to become widely prominent in the industry. 

Interchangeable parts and their effect on the world

The process of interchangeable parts transformed manufacturing from a high-skilled artisan-based profession into one that was low/ lower-skilled and in more of an assembly line production style. This ultimately increased productivity in the industry, lowered costs, and increased the number of jobs that were available to the public. 

The unfortunate side-effect of interchangeability was that it practically wiped out the world's class of skilled craftsmen. These skilled workers could no longer compete with high-volume manufacturing methods. Thus the professions were either completely eliminated or craftsmen were relegated to high cost artistic based labor. 

The History of Interchangeable Parts in the Industrial Revolution
Ford assembly line. Source: Public Domain/Wikimedia

Today, interchangeability and high-tolerances on manufactured parts practically define the entire world around us. If it wasn't for this, we wouldn't be able to fix practically anything around us without the help of expensive craftsmen. If your car broke for that matter, you'd have to leave it at a shop that would custom design a new part for it. Interchangeability changed the industrial revolution and thus changed the world.

Every single other invention that came out of the industrial revolution benefited from interchangeability, the steam engine, sewing machines, telegraphs, and more.

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