Last Updated on 6 months by Susan Mayrich
Sewing machines are designed to make sewing easier, but they can also cause problems if they’re not used correctly. One of these problems is threads bunching under the fabric.
Sewing machine thread bunching is usually due to a problem with the bobbin tension. This may be caused by several reasons, including a poorly wound bobbin or incorrect settings on your sewing machine.
Other reasons may cause sewing machine thread bunching. Let’s take a look at some of them so that we can solve this issue as quickly as possible.
Bobbin Tension Issues
The most common reason is that you have a problem with your bobbin case. It could be that the bobbin case tension is too tight or too loose. If this is the case, it may be causing the stitches to pull around the bobbin and bunch up underneath the fabric.
If you have a top-loading bobbin case, you will need to adjust the setting so that it matches the tension setting on your sewing machine. If you have a front-loading bobbin case, then you’ll want to make sure that the bobbin is wound properly so that it doesn’t cause bunching issues like these.
Incorrectly Set Needle Plate Height
Another reason why your sewing machine thread keeps bunching up underneath fabric is because of an incorrectly set needle plate height. The needle plate must be set properly for your sewing machine to function properly.
If your needle plate isn’t set correctly, then it will cause problems with your stitch quality as well as bunching underneath the fabric.
The Thread is Heavier
In some cases, this can also happen if you’re using a heavier weight thread than recommended on your sewing machine manual. Most manufacturers recommend using lightweight threads in their machines because they tend to work better than heavy-weight threads when used on a home sewing machine.
Incorrect Tension Settings
If your sewing machine has adjustable upper and lower tensions, then it’s time for some troubleshooting.
Check the bobbin tension and make sure that it is not too tight or loose.
A loose bobbin tension will cause your stitches to look messy and unevenly spaced while a tight bobbin tension can cause your stitches to pull out of place or bunch up beneath your fabric.
Your Thread Tails Are Short
You must leave a long tail of thread at the beginning and end of each seam (at least 6 inches long per inch of seam allowance). This will help keep the threads from tangling together and prevent bunching as they come out of the needle hole.
Your Feed Dogs Are Not Raised
When your feed dogs are raised (the part of the machine that moves fabrics), they help pull fabrics through with ease by creating a “comb” effect with each pass through a seam.
However, if they’re not raised, then all sorts of problems can occur like bunching or skipped stitches. Make sure your feed dogs are always up when sewing.
Your Presser Foot Is Raised
If your presser foot is not down all the way or not even touching the fabric at all, then that could be why there is bunching underneath the fabric while sewing.
Make sure that your presser foot is down onto your fabric before sewing so that there aren’t any gaps between it.
Bobbin Case Is Full of Lint
Lint in the bobbin case can cause a lot of problems with your sewing machine. When lint gathers on top of the bobbin case, it will stop the thread from coming out.
This means that you will end up with bunches of thread underneath your seam allowance and that is not what you want to happen.
You can remove lint from inside the bobbin case by using a small brush or a pipe cleaner dipped in alcohol and gently brushing away any lint you see. You can also use an old toothbrush which works well too.
Bobbin Not Inserted Correctly
For your sewing machine to work properly, the bobbin must be inserted correctly into the bobbin case. It should be placed so that its lip or opening faces away from you when you look at it from behind the machine (see picture below).
If it’s facing towards you, then the thread won’t feed properly through its eyelet hole causing it to bunch up underneath your fabric.
Incorrect Threading of Your Sewing Machine
Another possible reason for bunchy threads is if you don’t have enough tension on your machine or if there’s not enough pressure coming from underneath the needle bar to push down all of those layers of fabric at once.
Spool Cap Is Not Secure or Missing
The spool cap is a small plastic cap that screws on the top of the spool of thread. It keeps the thread from unrolling and bunching underneath the fabric.
If you are sewing with a lot of layers of fabric, it’s easy for the thread to bunch up under the presser foot because it doesn’t have enough room to feed through smoothly.
The solution is to make sure that your spool cap is securely fastened so that it stays in place while you are sewing.
Using Too Much Pressure on the Foot Pedal
When you use too much pressure on your foot pedal, it takes longer for the needle to move up and down through all of those layers of fabric and this can cause bunching under the fabric as well as skipped stitches and broken needles.
Try using less pressure on your foot pedal until you get used to how your machine works with different thicknesses of fabric and then gradually increase your speed after that until you find what works best for your machine.
Using a Worn-Out Needle
When you use a worn-out needle, your stitches will be wobbly and won’t sit straight in the fabric. It’s easy to tell if your needle is worn out, just look at it under a magnifying glass and see if it has any shiny areas where there should be no shine.
If you’re using an old, dull needle on your sewing machine, it will likely leave holes in your fabric. The only way to avoid this is to replace your old needle with a new one. If you notice any problems with the thread bunching up underneath the fabric while sewing, try replacing your needle.
Oiling Up Too Much Before Sewing
If you use too much oil on your bobbin case before putting on your spool of thread, there can be excess oil left behind when you’re sewing.
This excess oil can cause your bobbin case to stick together and make it harder for the top thread to pass through smoothly, resulting in bunching underneath the fabric.
To prevent this from happening, only put a tiny bit of oil on your bobbin case before putting on your spool of thread, then sew a few stitches without turning off your machine before removing the spool and replacing it with another one.
Sew with Too Heavy a Fabric for Your Machine
Using too heavy of fabric for your machine can also cause problems with getting good stitching results because it taxes the motor beyond its capabilities and causes it to strain while trying to move all that heavy fabric through it at once.