A Guide On How Does a Sewing Machine Work

How Does a Sewing Machine Work? Read Our Compelling Guide to Get the Idea

To respond to how a sewing machine work, we need to acknowledge two key principles which constitute the process.

According to Hobby Couture, modern or old, electronic or computerized, made by Singer, Brother, or other sewing machine brands, in other words, all sewing machines, since their beginning, have been working based on the mechanisms of

    • double-threaded stitching and
    • perfect synchronization of the stitching and fabric motion;

Despite how complicated sewing machines may look for newbies, operating them isn’t that hard. (view our take on a sewing machine for beginners)

The problem may only appear when we try to understand their functioning. 

Let’s take an up-close look at how this magic happens. 

Sewing machine how it works

Sewing is one of the most creative and powerful crafts spread throughout the globe. 

The sewing business has the potential to bring not only loads of dough to the people involved but also a heap sight happiness to 

    • fashion and textile enthusiasts, 
    • crafters at home, 
    • fashion designers, and 
    • clothing brands owners; 

It so happens that the people listed above are also a Super Label Store’s target group. The company offers 

    1. super easy to design and order, 
    2. in super quality, 
    3. super custom, and 
    4. available in super low quantities 

different types of woven labels, 100% ready to pump up your sewing projects!

Customize your textile, clothing, towels, sheets, and accessories with 

Hang tag large 2

If you’re new to the game, learn how to sew and explore sewing machine parts. It may come in handy when we explain details around the question, “What does a sewing machine do?”.

So are we ready to tackle the sewing machine working mechanism? If everyone’s on board, let’s grasp the idea straight away. 

Here is a brief explanation of how stuff works sewing machine animation:

Those who wish to dig deeper and grasp the mechanism from a more sophisticated angle should have a look at “How a sewing machine works” by Animagraffs:

How Stuff Works is right when they say that “the sewing machine takes something time-consuming and laborious and makes it fast and easy.”

Mind that sturdy, finely stitched clothes we can now buy for a couple of bucks were a luxury only 200 years ago. 

Find the best sewing machine for you and check these “15 Sewing Blogs You Need to Follow Right Now” on Craftsy.

How does a sewing machine work
Image source: Blog for Better Sewing

The automated stitching mechanism in the sewing machine is simple. Yet, the machinery itself looks pretty elaborate, with all its gears, pulleys, and motors varying in materials and sizes included. 

Authors of How Stuff Works compare a sewing machine to a car; both are built around one basic idea. The former has a heart as the internal combustion engine, the latter as the loop stitching system.

What does a sewing machine do in the loop stitch?

The loop stitch differs significantly from hand-sewing, where a thread is tied to a small eye at the end of a needle. 

In hand-sewing, the sewer passes the needle and the thread attached to it through two pieces of sewing fabric and back to bind two pieces of fabric together. 

This process would be too complicated for a sewing machine to pull off. 

So how does a sewing machine work instead? 

Sewing machines are quicker—they pass the needle only part-way through the fabric. 

Here comes a little adaptive adjustment in the needle anatomy: sewing machine needles feature the eye right behind the sharp point, not at the end. 

Since the eye of sewing machine needles is on the pointy end, it allows it to push the thread through the fabric without going through itself (as there is no need to do so).

Take a look at the overview of all sewing machine parts on The Yellow Peg

How a sewing machine works
Image source: Pinterest

The needle tied to the spool thread (also known as an upper thread) pierces the sewing fabric and the needle plate below it. The needle is driven up and down by the motor powered by a series of gears and cams.

The needle slightly rises so that the thread, pushed against the underside of the needle plate, folds into a loop—adds Hobby Couture.

The loop is caught by a rotating hook (the bobbin case) which widens it and makes it circle the case and the small bobbin within. 

The bobbin supplies the second thread coming from below (also referred to as the lower thread).

The lower thread is caught in the upper thread’s loop when the hook’s rotation ends. The combined forces of both threads make a knot. (we tackled sewing machine thread here)

A mechanism underneath the fabric grabs this loop and wraps it around either 

    • another piece of thread or 
    • another loop in the same thread;

Then, the needle pulls the upper thread back up, firmly tightening the knot against the fabric. 

The entire operation lasts a split second!

The stitch is done, and the machine can start the cycle again. 

There are a few types of loop stitches, all working differently.

The simplest loop stitch is the chain stitch, where the sewing machine loops a single length of thread back on itself. Read on DWInc about various sorts of stitches. 

Sewing machine mechanics
Image source: YouTube

We mentioned complex mechanisms inside the sewing machine. Learn to sew to have a taste of them in practice.

Belts, driveshafts, and cranks transform the motor’s rotation into a synchronized movement of

    • the needle and the two threads, for stitching (as described above)
    • the presser foot and the feed dogs, to pull the fabric forwards between creating any two stitches;

So how does it look on the inside? Sewing machine how does it work?

If you were to take the outer casing off, you would see a mass of gears, cams, cranks, and belts, all driven by a single electric motor. (sewing machine repair anyone?)

All machines vary, but the core idea is similar, and it’s quite genius! 

So let’s tackle the mechanism step by step, with some support from How Stuff Works:

A drive belt connects the electric motor to a drive wheel. 

The drive wheel rotates the long upper drive shaft—and the latter is connected to several different mechanical elements. 

The end of the shaft turns a crank, and what does a crank do?

    • pulls the needle bar up and down, 
    • moves the thread-tightening arm; 

The tightening arm moves in sync with the needle bar by

    1. lowering to create enough slack for a loop to form underneath the fabric, and then 
    2. pulling up to tighten the loop after it is released from the shuttle hook;

Now we got closer to what we can see and experience in our dressmaking.

The thread runs from a spool on the top of the machine, through 

    • the tightening arm and 
    • tension disc assembly;

By turning the disc assembly, you can tighten the thread feeding into the needle. The tension must be tighter when sewing thinner fabric and looser when sewing thicker fabric. 

Discover sewing machine tension features and issues with our blog.

The first element along the shaft is a belt that turns a lower drive shaft. Its end is connected to a set of bevel gears that rotates the shuttle assembly. Both are connected to the same driveshaft, so the shuttle assembly and the needle assembly always move in unison.

The lower drive shaft also moves linkages that operate the feed dog mechanism. 

And here comes the reason for the exciting balance each sewing machine achieves within its functioning. 

    1. One linkage slides the feed dog forward and backward with each cycle. 
    2. Another linkage, at the same time, moves the feed dog up and down. 

Since the two linkages are synchronized, the feed dog presses up against the fabric, shifts it forward, and then moves down to release the fabric. The feed dog then shifts backward before pressing up against the fabric again to repeat the cycle. (discover more on How Stuff Works)

Sewing machine on the inside
Image source: Sew Way

The motor that makes the sewing machine function is controlled by a foot pedal, which enables sewers to control the stitching speed. This instant foot pedal’s response to our command and feeling that everything depends on us is probably the most enjoyable part of sewing, except obviously creating projects. 

How does a computerized sewing machine work then? Is its functioning based on the same principles as the conventional electric sewing machine?

Sewing machines ‌we use at home nowadays have built-in computers and monitor displays for more effortless operation, which would indicate the entire sewing process also got transformed after two centuries.

The computer directly controls several different motors, which precisely move the needle bar, the tensioning discs, the feed dog, and other elements in the machine. 

Operating the sewing machine
Image source: Brainkart

Advancements in technology made it possible for modern computerized machines to produce hundreds of different stitches, store them in memory disks or cartridges, or even hook up to a PC to download patterns directly from the Internet.

Updated machines feature sensors that tell the computer how all the machine components are positioned. The computer prompts the sewer to replace the thread or make other adjustments when necessary. In other words, you can put your computerized sewing machine on the sewing machine table and go get yourself a coffee from a nearby bar. 

Has the core dynamic of a sewing machine’s functioning changed with all its complexity and jaw-dropping improvements?

You’ll be surprised that they are both built around the same simple stitching system where a needle passes a loop of thread through a piece of fabric, where it is wound around another length of thread.

What does a sewing machine do
Image source: Sailrite

How does a sewing machine stitch chain stitch?

Chain stitch is called this way because of the loops that hold together like a chain. 

In the making of a chain stitch, sewing fabric is sitting on a metal plate being held down by the presser foot. 

At the beginning of every stitch, the sewing machine needle creates a loop. Then, the looper mechanism, synchronized with the sewing machine needle, grabs the loop before the needle moves up. As soon as the needle gets out of the fabric, the feed dog moves the fabric forward.

The needle going down to start a new loop passes through the middle of the previous one. 

Things got a little complicated, didn’t they?

Now, the looper mechanism grabs that loop and wraps it around the next loop created by the needle.

A sewing machine is an incredibly ingenious tool!

Chain stitch jeans hem
Image source: Stitch Piece N Purl

How a sewing machine works on creating a lock stitch?

The lock stitch is sturdy, and it’s available on most sewing machines.

In general, the lock stitch operates like a chain stitch. 

But instead of chaining the thread together like in the chain stitch, a machine adds more thread (using the bobbin) which is then used to lock the stitch in place.

A bobbin assembly and the shuttle hook are crucial sewing machine parts for the lock stitch. 

Using the motor’s power, the bobbin takes thread underneath the fabric and dispenses its thread.

The needle pulls the loop through the fabric, and the feed dog moves that fabric, like in the chain stitch. 

Then, the stitch is locked to the bobbin thread instead of its following fellow loops.

When the needle creates the loop, the shuttle hook grabs the loop and pulls it around the thread coming from the bobbin. 

This technique creates a firm stitch that can support a lot of wear and tear.

Let’s see the differences between the two stitches mentioned above in the table below. (created with the help of Garments Merchandising)

Chain stitch Lock stitch
Formed by two or more sets of threads: needle thread and looper thread Formed by two sets of a thread: needle thread and bobbin thread
Thread consumption is higher than lock stitch

Thread consumption is less than chain stitches

How to thread a sewing machine?

Sewing threads are bound together by interloping and interlacing Sewing threads are bound together by interlacing
More seam puckering Less seam puckering than in the chain stitch 
Greater strength than lock stitches Lesser strength than chain stitches
Extensibility stands typically at 30% Extensibility is less than 30%
The appearance of stitches is similar to lock stitches at the top side and a double chain on the underside The appearance of the stitch is the same on both sides
We don’t need back tacking at the finishing end of the stitch We need back tacking in starting and finishing the stitch
Speed at 8000 spm Speed at 6000 spm

These were dry facts, but what about the experience? Heddels shares a bit of insight into the pros and cons of using both options:

Pros Cons
Chain stitch
    • more authentic and original,
    • results in a nicer fading pattern around denim bottoms,
    • better effects (i.e., twisted, rope-like look at denim bottoms);
    • can be done on a particular sewing machine,
    • tends to unravel,
    • only noticeable on the inside (i.e., after you cuff);
Lock stitch
    • stronger stitch,
    • cheaper,
    • more accessible;
    • aesthetically less natural (there are differences between denim, material, though)
    • less appealing because of a weaker “roping” effect

Discover more Super Label Store’s sewing-related blogs, such as

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