The Surprising Genius of Sewing Machines

- Can you explain how a sewing machine works? I mean, think about it. We've all seen them.

There's that little needle that's moving up and down really fast, leaving a trail of stitches behind them. But if you think about it for a second, how are they doing it? Because the needle is never actually going fully through the fabric.

If you're hand sewing, you have to pass the needle up and down. You have to let go of the needle and grab onto it on the other side. So in order to invent the sewing machine, we first had to invent a whole new way of sewing.

It's one of these things that almost no one thinks about, but is so important. Every piece of clothing you've ever put on virtually was made by a sewing machine. So in this video, I'm going to explain how sewing machines work.

And I promise when you find out, you will find it so incredibly satisfying. And what you'll realize is that these machines are performing tiny mechanical miracles every second. A part of this video was brought to you by KiwiCo, more about them at the end of the show.

- The foot pedal is right in front of your right foot. You can gently rest it. It doesn't need a lot of pressure.

So easy does it, and you should be able to start going. - All right. Ah, all right.

(sewing machine rumbling) This is amazing. - [Noah] I find it meditative. - If I were going to sew two pieces of fabric together, this is how I would do it.

Weaving the needle back and forth through both pieces of fabric. This is known as a running stitch, and there are more sophisticated stitches you could do. But if you're trying to mechanize any hand stitch, you run into a major problem, which is that any time you pass the needle through the fabric, you have to release it on one side and pick it up again on the other side.

This is almost impossible for a machine to do, at least a machine from 200 years ago. So in order to invent the sewing machine, we first needed to come up with a totally new way of sewing. And this came in three breakthroughs.

(dramatic music) Human have been sewing clothes for tens of thousands of years. In 2016, researchers found a needle in a cave in Siberia that dates back to about 50,000 years ago. The crazy thing is that homo sapiens didn't live in that cave.

It was inhabited by the Denisovans, a now extinct species of early humans. So sewing isn't just a homo sapien thing, it is a human thing. The needle is made of bone.

But in other regards, it looks like any modern needle, a sharp end pierced through fabric and an eye on the other end for the thread. Needles have remained basically unchanged for tens of thousands of years. Artifacts from caves in France, ancient Egypt, Greece, India, China, and Japan, all look about the same.

That is until 1755. Charles Frederick Wiesenthal was a German inventor living in England. We're not exactly sure what motivated him, some believe he was trying to invent a sewing machine, but maybe he was just tired of flipping the needle over twice every stitch.

But what he created was a needle that was sharp on both sides, so you could pass the needle back and forth through the fabric without flipping it over. He patented his invention, a needle for ornamenting fabrics, which may have sped up sewing a little. But the two-sided needle delivered an unexpected benefit used by all sewing machines up until this day.

It moved the eye of the needle next to the sharp tip. But how does that help? When I put the needle into the fabric, the thread does go below the fabric, but when I pull it out, the thread also gets pulled out.

So it seems like we've achieved nothing. We need to find a way to tangle the thread when it's at the bottom of the stitch to stop it from pulling out. And luckily, there are two ways of doing this.

(dramatic music) If you can keep a loop of thread underneath the fabric, as I pull the needle out, well then, I can move the fabric over and pass that needle through the loop, forming a little link. And if I do that again, I can form a chain of these stitches. That is why this is known as a chain stitch.

The chain stitch was one of the first stitches successfully performed by sewing machines. It's really hard to say who invented the first sewing machine. There were just so many people working on the problem at the same time and there are many competing claims.

In 1790, Thomas Saint drew detailed patent drawings for a sewing machine design, but there is no evidence that he ever built a prototype. In 1814, Joseph Madersperger was granted a patent in Vienna. It took him a decade to build the machine, but he never commercialized it.

He spent the rest of his life trying to perfect the design. In 1830, Frenchman Barthélemy Thimonnier built his own version. It created a chain stitch with a barb needle.

He was granted a patent and set up a garment factory with 80 of his machines. There, they began manufacturing uniforms for the French army but this invention caused an uproar. A mob of 200 angry tailors ransacked his factory and destroyed all of his machines.

It took a few more decades before sewing machines were reliable enough to be commercially viable. The two most reliable ways to build a chain stitch machine were invented at nearly the same time in 1857, when James Gibbs and Charles Raymond received their respective patents. It was easy enough for me to grab the loop of thread in the model, but it's much more difficult to design a machine to do this reliably and repeatedly.

Charles Raymond's design used a hook. The needle punctures the fabric and carries the thread down with it. Then as the needle moves up, the thread between the eye and the fabric shortens and buckles forming a little bulge of thread.

At exactly this instant, the sharp hook catches the bulge, stretching it into a loop. And as the needle comes back down, the hook moves backwards and the needle passes through the loop. The needle comes all the way down and then as it moves back up, the thread between the eye and the fabric buckles again, the hook catches this bulge pulling the thread into a loop for the needle to pass through once more.

Gibbs had a similar design, but the hook was rotating. So as the needle lowers the hook grabs the thread, the rotating hook spins around, the first loop is released, and then the hook grabs the second loop. It took Gibbs thirty-seven prototypes, all carved outta wood to get this incredible looper shape just right and then that same shape was used on over 80 models of sewing machines for 80 years.

The looper was held by pieces of metal tightly enough that it didn't fall out, but with enough of a gap for the thread to pass through all the way around. We are showing a simplified model here for clarity. But there's a flaw with this simple way of making a chain stitch.

If the thread comes loose, you can easily pull out all the stitching. It's remarkable how quickly and easily the thread gets pulled out because there's barely any friction with the fabric. The only friction holding each stitch in place is the loop from the previous stitch.

So once one goes, they just all go in a chain. So people developed more complex chain stitches that use more thread and are more robust. You'll likely find chain stitches holding the hem of your jeans together.

You can also embroider beautiful patterns with the chain stitch. - Anything that kind of had decorative stitches is what it was originally used for, but then it became used for all kind of lettering and flowers. - You're sort of doing gymnastics figuring out, if I feel it this direction, where is my next path gonna be?

You're trying to kind of think ahead of yourself. And I think as you become more skilled with the chains too, that's where your work begins to look a lot more refined. (sewing machine rumbling) - Besides the chain stitch, there is a completely different way to secure the thread.

And honestly, it's kind of genius. All it requires is two separate spools of thread. Now this spool of thread is called the bobbin.

So here's how it works. The needle goes through two pieces of fabric all the way down, and then you pass the second spool of thread completely through a loop in the top spool, and then bring the needle back up, pull in the excess and what we have done is interlocked these two pieces of thread. That's why this is known as a lock stitch.

In 1846, Elias Howe patented it and to promote his new creation, he staged a live sewing demonstration, him and his sewing machine versus five seamstresses. Howe's machine worked, but it wasn't elegant. The machine used a curved needle, the fabric hung down vertically, and it could only make stitches in a straight line.

Five years later, Allen B. Wilson dramatically improved the lock stitch sewing machine receiving two patents, one in 1850 and one in 1851. The first patent was for the vibrating shuttle lock stitch machine.

Although it's called a vibrating shuttle, it actually oscillates back and forth and inside it is a small bobbin of thread. As it moves forward, it catches the top thread from the needle forming a loop and as the shuttle passes through this loop, it creates a lock stitch by intertwining the top thread with the lower bobbin thread. The shuttles movement is synchronized with the needles up-and-down motion.

The shuttle was pushed around by pieces of metal tightly enough that it didn't fall out, but with enough of a gap for the thread to pass all the way around the shuttle. This type of sewing machine was incredibly common in the late 1800s. Many millions of just the Singer Model 27 were made, and they were built incredibly robustly.

There are many machines that are now over a hundred years old that are still working. Sewing machines were developed before the idea of planned obsolescence took off. The second patent that Wilson received in 1851 is the basis for how most modern sewing machines work.

Instead of a shuttle moving back and forth, the bobbin is inside a rotating hook. So let's see how that works. The needle comes down, pulling that top thread, and it goes down really low, and then it pops back up a little bit creating this little bulge right here.

And when the rotating hook comes around, it is grabbed by that rotating hook, pulling even more thread so that this thread can pass entirely around the bobbin. And then needle pops back up. We pull in the excess and we've formed another lock stitch like so.

From this, it might look like you're using more thread from the top because when this thread comes in, you need to pass an entire loop around the bobbin but that thread then gets pulled back up. So we actually filmed in slow motion a sewing machine using a gradient thread so you can see just how much thread is getting pulled in from the top. It looks like a lot, but ultimately you use the same amount of thread from the top spool as from the bottom spool.

The tension needs to be identical on both the top and bottom thread so the same amount of thread is used in each stitch. If the tension is off, the stitch won't meet perfectly in the middle of the two fabrics leading to a much weaker stitch. This is true for both vibrating shuttle and rotating hook lock stitch machines.

But what does result is a lot of friction. You can imagine this piece of thread is getting pulled back down and back up a whole bunch of times with every stitch. So what was developed was actually a groove in the sewing needle right here to reduce the friction between the thread and the fabric as it has to keep getting pulled down to go around the bobbin and then get pulled back up when it's tensioned again.

This resulted in less fraying of both thread and fabric and resulted in a cleaner stitch. Practically all modern sewing machine needles have a groove on one side. But there's still an important piece missing.

After a stitch has been made, how do you move the fabric? (dramatic music) In the earliest sewing machines, the fabric would be moved by hand after every stitch, but that was obviously slow, inefficient, and the stitches wouldn't have been identically spaced. A few designs were attempted, but the most successful one was also invented by Allen B.

Wilson. His idea was a small piece of metal, the foot that would press down on the fabric. When the needle is not in the fabric, a small piece of metal with grooves in it pushes up from below.

It grabs the fabric and then moves back a fraction of an inch advancing it to where the next stitch should be. This design is used in practically all sewing machines today. They're called feed dogs.

There are some modified versions of this idea, like the universal feed machine used for chain stitch embroidery. - With these style of machines, there's a handle underneath the machine and it rotates the entire nose of the machine. - [Derek] Okay.

- And this presser foot, that will basically advance the fabric in 360 degrees. So right now we've got this hooked up to a single motor, but back then these cables went up to the ceiling and were all powered by one big generator, one big like steam power or coal powered generator. And so I'm sure the factories were so loud.

There used to be a pin, we've taken them off just 'cause we don't need them anymore. And what you would do is you'd pull down and it would immediately engage the machine because this was spinning continuously 'cause it was all hooked up by one motor. Like nowadays, when you start a machine, you can kind of like feather it a little bit, you can start slow.

Back then, they were going like 10,000 rpm right away. - [Derek] You got to gotta be ready. - Yep.

Those women were heroes. I mean, unbelievable skill. - The most famous name associated with sewing machines is that of Isaac Singer.

But Singer did not invent the sewing machine. He was a shrewd businessman buying up patents for various parts and building his company on that. Inspired by interchangeable parts that he saw in production of firearms, he optimized the production process and his company was able to drop the price of sewing machines from a hundred dollars to around $10.

That's just over $300 in 2023 terms. This lower price meant he could sell the machines to families rather than to corporations. Singer's business was also one of the earliest in the world to offer an installment payment plan, allowing the buyer to pay it off over a few months, rather than paying the entire cost upfront.

Singer became one of the largest corporations in the world and the first American multinational company. Before the advent of sewing machines, it would take over 12 hours to sew a single shirt. It now takes less than 30 minutes.

In 1900, the average American family spent about 15% of its total income on clothing. In 2003, it was less than 4%, but despite spending less, we own more clothes. In 2019, the worldwide average number of garments owned was over 130.

Each year, a hundred billion garments are produced. And just in the US alone, 11. 3 million tons of clothing ends up in landfill.

That's nearly 35 kilograms of clothing for every man, woman, and child that is thrown away each year. But should we blame sewing machines? The sewing machine is brilliant.

Invented, iterated upon, and improved by dozens of people. They really have revolutionized the world. All it took was inventing a completely new way to sew.

Hey, this part of the video was brought to you by KiwiCo, a company that's all about making science and learning about the world fun and engaging. I know that the best way to learn is through interactivity and I personally got a much better understanding of sewing machines by building models, actually using a sewing machine, taking it apart and putting it back together. Now, KiwiCo have been a longtime sponsor of the channel because they genuinely make great products.

I mean, my children love them. Not only are they a great learning tool, but they're also really fun. When the crates arrive at my doorstep, my kids can't wait to open them and start putting the projects together.

This month we built a coin eating robot, and amidst all the fun they were having, there were also lessons in electric circuitry, cams and mechanical linkages. Each crate comes with all the the materials you need, detailed instructions and an explanation of the science behind the project. It's so nice that everything is there and ready to go, so you don't need to run out to the store or gather any extra supplies.

I can just enjoy quality time playing and learning with my kids. The crates are designed by experts to be educational and enjoyable, and they have different product lines to cater to all age groups down to newborns. KiwiCo believes that the best way to learn is by doing, and that is definitely a philosophy I can get behind.

So go to kiwico. com/veritasium to get your first month's crate free. This offer is exclusive to Veritasium viewers, and with the holiday season coming up, this is your friendly reminder that KiwiCo crates also make great gifts.

So go to kiwico. com/veritasium, subscribe and get your first month's crate for free. I want to thank KiwiCo for sponsoring this part of the video, and I wanna thank you for watching.