How Does A Sewing Machine Sew?

Like all Hackaday readers, we pride ourselves on having at least a passing acquaintance with how most things work. But we suspect to a lot of people, things we take for granted — computers, air conditioning, motors, and cell phones — are just black magic. That’s how we feel about sewing machines. Sure, there’s a motor. There’s a needle and some thread. But how does the machine make a stitch? We always wondered, but after watching a recent video from [Veritasium] we can at least claim we have an idea.

First, he shows the intrinsic problem: sewing by hand requires you to reverse the direction of the needle, and it isn’t clear how to make a simple machine to do that. Sure, today you could probably make a robot that sews like a human does, but sewing machines have been around for a very long time.

In addition to showing how a chain stitch and lock stitch work, the video shows the history of the machines, including 50,000-year-old needles and the progression of innovations required to get to the modern sewing machine. In addition, he shows a large model sewing machine to clearly explain the concepts.

You might think you don’t care about sewing, but machine sewing has touched nearly everyone. The video says that in 1900, a family might spend 15% of their income on clothes. In 2003, that number drops to under 4%, yet the family will have many more clothes than they did in 1900. This is possible because of machine sewing and other innovations.

You can, of course, make your own sewing machine. If you want to get an industrial one, we have some advice.

35 thoughts on “How Does A Sewing Machine Sew?

  1. “You might think you don’t care about sewing, but machine sewing has touched nearly everyone.”

    That’s so true. For a while, we had sewing in school as a school subject, even.
    Ah, I remember these good old Pfaff machines.. :D

    1. I sewed a new zipper to a hoodie for the first time in my life today, with the Pfaff 332 from 1957 that I inherited from my grandmother.

      There were some pieces it didn’t cope (13 layers of fabric on top of each other) but then I tried to manually seam those pieces and boy, do I have some respect for that machine now!

  2. “It isn’t clear how to reverse the directionof the needle”. I’ll have to watch the video; I just assumed it was a crank all along, you know the simple machine that converts rotary motion to linear motion. /s

    1. Ohhh reading fail. I see now you meant feed the needle from another direction, not merely reverse its travel. I highly recommend Tim Hunkins “Secret Life of Machines”. It has an episode on the sewing machine.

  3. Machine stitches use a type of stitch commonly performed in leather working. I believe it is a lock stitch. Whatever the name, your swiss army knife has the necessary punch with a thread hole.

    1. Not quite. When one says “leather working stitch”, they usually mean “saddle stitch”. In saddle stitch those two threads go back and forth both sides for a length of one stitch at a time, in machine lock stitch top thread stays top and bottom thread stays under all the time, they just twist in the middle.

  4. A worthy alternative was the immortal Tim Hunkin (of “Secret Life of Components” series) who did a “human sewing machine” episode: The thing always to keep in mind that if anything remotely ‘knot’ is involved then some portion of the line has to be passed through the loop in the line elsewhere. (with Hunkin’s video one human being just passes the bobbin through a loop)

  5. A friend gave me a basic sewing machine years ago. I’ve used it to make a mattress cover, black out curtains, and fix holes in the armpits of my favorite t-shirts. I even took a dress shirt that didn’t fit well and trimmed the sides and arms and now it fits like a dream. If you’re handy with wood, metal, plastic etc., why not be handy with fabric as well.

      1. The sewing machine won’t be handy if the apocalypse includes no electricity. Better learn to spin, weave, sew, and knit by hand. Oh, and don’t forget to plant cotton, flax, and/or hemp and raise some sheep, llamas, or alpacas.

  6. Have restored moms old Pfaff sewing machine with help of a german forum. Holy cow do you need a lot to know about cleaning chemicals, lubricants and so on, which reacts which what. May be a everyday knowledge 50 years ago, but if you grow up electronics, PCs and so on and have newer experienced mechanical stuff, this sewing thing looks like a enigma :-)

      1. There are alot of these machines still in existence and parts are pretty much readily available. Also they are almost simple enough for the average joe to work on. I’m reasonably sure any repair shop would take one of these over anything modern.

        1. Sort of; there are a few machines where there are no parts, because there’s no one around that remembers that brand, where the brand had the machines made, and what model it was a clone of. I have two ‘vintage’ machines dating from the late 50’s or early 60’s, one of which I am the second owner of. (A Coronado 45-4116A, probably made by Brother) the other one is a “Super Automatic model 114” in a lovely Avacado Green that I can’t find information for on the internet to save my soul, and the manual for it(!), while in fantastic shape, doesn’t list any dealer or manufacturer information in it.

          I have the manual for the Coronado, and the Internet Archive has the scanned copy I made of it last year.

          1. There are no spare parts for old Bernina machines because a flood engulfed the basement of the factory where the machine tools for making them were stored, and they were lost for ever.

            The old Singer Featherweight (not to be confused with the modern attempt to capitalize in its name) is a lovely little machine, very sought after because of its small size and good stitch quality, and there’s quite a community of its fans.

  7. Sewing is just another tool in your toolbox, and a great skill to have. I have sewn a lot, and it was mostly stuff I couldn’t buy. Special backpacks, pouches, webbing gear, webbing harnesses, custom slings and so on. I really need a stronger machine as it struggle with 10 layers of cordura+webbing+zippers or something, but the layers quickly add up in more complex work. Occasionally I need to use needle and pliers while sewing by hand, because it’s just not possible to get it into the machine. Fixing pants, or converting to shorts and such is easy.

    The irony is, sewing might be seen as typically female thing to do, but my sisters and mother borrow my sewing machine and kit when they need to sew difficult or tough materials.

    1. Same for me until I broke the bank and got a Sailrite, best purchase (after a mantis) walking foot, heavy duty.
      But I had to replace the motor with a 48V BLDC instead of the crappy original motor (that would be a nice write-up here)

    1. It is surprising where Singer sewing machines show up.

      I see them all the time in the background of movies.

      More surprisingly, I see them in the background of travel documentaries.

      There’ll be an interview with someone in a village out back of beyond in Africa or Asia somewhere, and in the background you’ll often see a Singer treadle machine clacking away as someone makes or repairs clothing.

      The old things are tough and reliable. Keep them clean and oiled and they’ll run for decades.

      They don’t need electricity, and all you need to maintain them is oil and some hand tools. If the belt breaks, you can patch it together with another clip – or replace it with a piece of heavy twine or light rope.

  8. Not a bad video.

    As a fan of vintage sewing machines (, however, I must make one correction.

    What he called a vibrating shuttle is in fact a transverse shuttle.

    A transverse shuttle runs back and forth in a straight line between the column on the right going towards and past the needle on the left.

    A vibrating shuttle swings in an arc from the front to the back of the machine. That’s the short way across the bed of the machine.

    There’s a considerable difference between the function of a vibrating shuttle and a transverse shuttle. More importantly, from a practical point of view, transverse shuttle machines nearly all use oddball needles that are no longer manufactured while many vibrating shuttle machines (though not all) use needles that are still being made today.

    The video shows the motions of a transverse shuttle but calls it a vibrating shuttle.

    The Wikipedia article on sewing machine bobbin drivers has drawings that show the difference between vibrating shuttles and transverse shuttles.

    1. While true, there is transverse shuttle in the video, same model can be also used for demonstrating vibrating shuttle. Movement of shuttle is exactly the same in both in relation to needle and thread loop. Whole mechanism (needle and shuttle) is just turned 90 degrees. In vibrating shuttle shuttle moves vertically and needle hole is sideways, in transverse shuttle model shuttle moves horizontally and needle hole is front to back. There are differences in other parts inside machines, but when it comes to this scale model in video they are both identical.

  9. Thinking a little bit more about why sewing machines don’t emulate hand sewing: the problem isn’t so much the fact that the needle is pulled through the fabric, but rather that the entire length of the thread is also. When hand-sewing, you need to figure out how much thread you’re going to use ahead of time, and get at least that much onto the needle. You then pull all that thread through the stitches until you’re left with very little at the end of the job. In fact, sometimes you don’t have enough, so you have to tie it off early and get some more thread for another go. If you use too much thread, then you’re spending a lot of time pulling it through the stitches, and you’re left with extra thread at the end that you’re never sure what to do with.

    On the other hand, sewing machines let you load a whole bunch of thread, and they only push enough thread through a stitch as is needed to make that one stitch. They can keep on sewing as much as you want, without anyone having to measure out the thread ahead of time, since it’s fine to have more than enough.

  10. If you liked this marvelous build that demystifies the inner workings of the late 19th century sewing machine, you will love this turn of the 21st century “Junkyard Wars” TV show audition tape by team “The NERDS.” (apologies for the VHS quality, still the brilliance does shine through)
    For the impatient, at 0:01:34 the three-humans-playing-sewing-machine demonstration begins. Enjoy!

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