Replaceable Parts The keys to the modern world. In many ways replaceable parts make modern transportation possible. The concept of replaceable or interchangeable parts is of tremendous importance to both the History of Transportation, and to History in general, and one merely has to take a trip to the local auto parts store to understand the importance of this concept to keeping our modern world running smoothly.
Who invented replaceable parts is a question with several answers. The French had been making guns with interchangeable barrels since the mid 1700’s, and a Virginian named Stephen McCormick had been selling plows with changeable and replaceable blades in the early 1800’s. But, the credit usually goes to Eli Whitney who pioneered mass production of machine made parts that could be made to specifications for later assembly and used on his cotton gin.
Thus, Eli Whitney made not only large scale use of cotton in the textile industry possible with his gin, but also pioneered modern manufacturing. Rather than skilled craftsmen custom making each part of whatever device they were constructing to fit that device, now semi-skilled or unskilled machine operators could turn out thousands of parts that could be used to build new machines, or replace worn or broken parts on existing machines. This is a huge key concept that rests at the very root of the Industrial Age itself. Doubtless, if Whitney had not done this someone else would have, as this was the proverbial concept whose “time had come”, but as far as I know he is the first large scale manufacturer of machined interchangeable parts.
My mind is telling me that Remington, or Winchester, or one of the 19th century gun manufacturers is also sometimes given credit for replaceable parts, and in a military context this is almost certainly somewhat true, but my current research is not confirming this vague memory. Even so, both Whitney and Stephen McCormick predate the gun contracts which are stuck in my mind by a few decades or so, to the best of my current knowledge.
Irregardless, the effect of this concept on transportation is huge when it is eventually applied to locomotives, and later automobiles. Henry Ford added the assembly line to interchangeable parts, and moved industry another giant leap forward.
Auto parts stores would not exist without replaceable parts. Imagine a world in which your car broke down, and you not only had to find someone with the skills and knowledge to repair it, but also someone that could make the part your mechanic needed by hand from scratch. That was the world before interchangeable parts.