Your Key to Sewing Machine Troubleshooting
An understanding how sewing machines work helps you diagnosis your own sewing machine problems.
This online primer 'uncovers' the internal workings of your machine and how even the slightest misalignment can effect its performance—AND your sanity.
Sometimes something as innocent as a damaged needle point can prevent your machine from making a stitch.
Replacing the needle is almost always my first recommendation when something goes awry with your machine! It's that simple. But that important.
If you could remove the cover of your machine, you'd quickly discover how simple the basic machine truly is. And why it doesn't take much to throw it out of kilter.
Computer parts aside, the workhorse parts of your machine are:
Now let's see how all the parts work together.
A video follows to illustrate this example.
Throughout the process balanced tension from the needle and bobbin keep the stitch in the center of the fabric.
This process repeats for every stitch.
To keep each step in order and humming along, these parts are connected by belts to a single motor. The same shaft that moves the needle with one belt and moves both the rotary hook and feed dogs with another belt. Two belts plus one motor equals synchronicity!
Domestic sewing machines stitch along at approximately 840 stitches per minute (newer models are even faster—up to 1600 spm). So it's crucial the parts work together correctly and orderly. If they're not in sync, then 'your timing is off' and it'll take a trip to the repair shop to get it fixed.
Now it's easy to get a look at the inside workings on older machines by simply unscrewing the cover.
Most newer models, especially those with computerized innards, require specialized tools to remove the cover properly and these tools don't usually come with your machine.
This video shows exactly how a stitch is formed without any manufacturer's razzle-dazzle. A well-spent 27 seconds!
Thank goodness the video slows things down enough so that we can see the process of making a stitch.
Can you imagine how fast it'd be moving on a newer machine capable of stitching 1600 stitches/minute?
...about how sewing machines work to help solve your machine problems.
It should start to make sense why your sewing machine needle is so important and why it's prudent to keep extras on hand to quickly determine if the problem IS your needle.
If it's not inserted all the way, it pushes further into your machine as it passes thru the throat-plate. The loop will either not form correctly or not form at the proper time. The rotary hook won't be able to catch the loop to form the stitch.
A bent or damaged needle deflects as it pierces the fabric. Again, it won't be in the correct position for the rotary hook to catch the loop.
If the rotary hook doesn't catch the loop to twist the threads together, you've got skipped stitches.
If the thread doesn't flow smoothly around the hook, you'll have skipped stitches.
Many Christmases ago, I unknowingly wore a grove into my rotary hook and shuttle assembly by pulling my piecing out from under the needle when the uptake arm wasn't in it's highest position. The tension on the thread and repeated pulling action wore a groove into the rotary hook and shuttle that had to be polished out by my dealer.
If your tension isn't balanced, that can effect when the loop is formed. Or how big it is or isn't. Too small means a skipped stitch. Too big is the beginning of a thread nest.
Use what you've learned about how a stitch is formed to help you reason through many of the most common problems.
This last video, a bit longer than the first, adds a bit of history on the beginnings of the sewing machine. It is humorous, with good visuals of how sewing machines work using humans for the parts of the machine that make a stitch. Enjoy!
Now that you understand how sewing machines work, you may be interested in these pages:
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