The assembly line – which began in the slaughterhouse, not the car factory
Not recorded yet Host Jan Sindre Heltne
The assembly line was not invented in the car industry. It came from the Chicago slaughterhouses, where animals were taken apart on rails. Here is how the idea was reversed, what happened to the price – and what it cost the people standing at the line.
The assembly line is the most copied idea in industrial history, and it did not come from the car industry.
It came from the slaughterhouses.
The line that ran the other way
In the slaughterhouses of Chicago and Cincinnati in the late nineteenth century, carcasses hung from overhead rails. A trolley carried them from worker to worker, and each person made one particular cut before the carcass moved on.
It was not an assembly line. It was a disassembly line.
What moved: the workpiece, not the worker.
What stayed put: the human being, with one cut and one tool.
What Ford saw: that the direction did not matter. If you could take something apart this way, you could put something together in exactly the same way.
That is the whole invention, and it looks strikingly simple written down: move the workpiece, not the worker.
How cars were built before
To see how large this was, you need to know how a car actually came into being before 1913. And it was not mass production in any sense.
In the 1890s, car building was a craft. Parts were formed in one workshop, hardened, and distorted in the hardening. Then they were machined again. And finally, parts coming from different workshops were filed and worked by hand by skilled fitters until they matched one another.
Two ways to make a door fit
Craft
The part is fitted to the car
- The door is worked until it fits this particular frame
- Every car ends up slightly different from the last
- The deviations accumulate through the car
- A door from one car does not fit another
- Requires a skilled fitter at every joint
Mass production
The part is the same every time
- The door is made within a tolerance
- Every frame is within the same tolerance
- No adjustment needed
- Any door fits any car
- Requires gauges, not craftsmen
What Ford really invented
Here is the nuance that usually drops out: Ford did not invent interchangeable parts. He did not invent gauging, and he did not invent machines able to cut hardened metal.
What he achieved first, in 1908, was parts precise enough that they did not have to be finished by hand. That is the real threshold. Without it an assembly line is worthless, because the line stops the moment somebody has to stand there filing.
The order that made it possible
- First: precise partsParts must fit without adjustment. This came in 1908, five years before the line.
- Then: fixed division of labourEach worker performs one operation, in one place, every time.
- Then: move the workpieceThe car is carried past the workers instead of the workers walking to the car.
Highland Park
Ford’s first moving line was installed at Highland Park in early 1913, and it was not for the whole car – it was for flywheel magnetos. From there the principle spread through the factory.
Before and after, in numbers
| Measure | Before | After |
|---|---|---|
| Time per chassis | Around 12.5 hours | 93 minutes |
| Rate in 1914 | — | A Model T every 24 seconds |
| Production 1914 | — | Over 202,000 cars |
The price
The consequence for the customer is the part people remember, and it is dramatic.
Model T, price over time
ExpensiveCheap
What it cost
Here comes the part that rarely appears in the edifying version of the story, and it is necessary to understand the rest.
The work at the line was so monotonous and so hard that people left in large numbers. By late 1913, turnover at Ford was 380 per cent. The factory effectively had to hire almost four people to keep one position filled through the year.
The five dollar day was not generosity. It was the price of getting people to stay.
What applied before: $2.34 for a nine-hour day.
What came in January 1914: five dollars for an eight-hour day.
What it bought: that people were willing to submit to the pace and discipline of the line.
Why it is worth saying plainly: the pace did not get gentler. The compensation got higher. Those are two entirely different things, and the difference is the whole point.
What the line does to work
Finally, the part worth carrying forward, and it applies far beyond car factories.
Who sets the pace
Without a line
The worker
- You decide when to take the next part
- You can spend extra time on something difficult
- You can catch up later
- Variation in pace is invisible from outside
With a line
The line
- The next unit arrives regardless
- If you fall behind, everyone sees it
- You cannot catch up – only stop everything
- The pace is a setting, not a negotiation
What is worth taking with you
That the assembly line came from the slaughterhouses, and that it originally ran the other way.
That the invention is one sentence: move the workpiece, not the worker.
That it was not possible until parts were precise enough that nobody had to file and hammer them into place.
That time per chassis fell from around 12.5 hours to 93 minutes, and the price from $850 to $260.
And that turnover was 380 per cent before the five dollar day – because the line did not only make the work faster, it took the control over pace away from the worker.
Figures and dates are from The Henry Ford and the Library of Congress. The account of craft production before 1913 draws on Womack, Jones and Roos in The Machine That Changed the World.
Main topics
- Where the idea actually came from
- The slaughter line, reversed
- How cars were built before
- What Ford really invented
- Highland Park, and the numbers
- The price that fell
- What it cost the people
- What the line does to work
Questions this episode answers
- Who invented the assembly line?
- What does pig slaughter have to do with building cars?
- How were cars built before the assembly line?
- Why did doors have to be fitted by hand?
- How much faster did production get?
- Why did Ford introduce the five dollar day?
- What is actually new about an assembly line?
Key points
- The idea came from the Chicago slaughterhouses, where animals hung on rails and were taken apart – not put together.
- Ford reversed the disassembly line into an assembly line.
- Before this, parts were filed and worked by hand until they fitted, and every car was unique.
- What Ford achieved first was parts precise enough that they needed no hand-finishing.
- A chassis went from around 12.5 hours to 93 minutes.
- In 1914 a Model T came off the line every 24 seconds.
- The price fell from $850 in 1908 to $260 in 1924.
- Turnover was 380 per cent in 1913. The five dollar day came in January 1914.
Sources and references
- The Henry Ford – Assembly Line (research guide)
- Library of Congress – Ford Implements the Moving Assembly Line
- The Henry Ford – Crowd of Applicants outside Highland Park Plant after Five Dollar Day Announcement, January 1914
- James P. Womack, Daniel T. Jones and Daniel Roos – The Machine That Changed the World (1990)
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