I'm getting loops on the surface of my fabric. I have rethreaded both upper and bobbin and played with the tension.

Is it actually the bobbin thread that loops or is the loop appearing on the underside of the fabric as you stitch? If it is a loop under the fabric, that's usually an indication it is an upper thread issue. Thread irregularities that appear on the topside of the fabric are generally bobbin related.

First thing to try is installing a brand new needle. Verify it is the correct needle for the fabric and thread being used.
All About Needles
Sometimes, the fabric being stitched will "grab" the thread and hold it for a second before releasing and will cause a loop. In this case, a needle with a larger scarf and eye may be helpful.

You might also open the upper tension as much as possible, RAISE the presser foot and run a piece of UNwaxed dental floss through the tension disk a few times to clear out any gunk that may be stuck there. A piece of pearl cotton dipped in rubbing alcohol and squeezed moist/dry will also work.

Remove the upper thread. RAISE the presser foot and rethread the top thread from the beginning. Use only fresh, good quality thread--NO old or bargain bin variety! Try using the same thread in the top and bobbin. Make sure the thread is firmly seated in the tension disk and the thread path is correct. Check that there are no burrs or snags in the thread path that could be catching the upper thread. Especially, check that the thread is not catching on the spool "slit" that holds the thread when in storage. Every time the thread navigates around the thread spool, it could be catching on that slit just enough to cause a loop.

Try changing the bobbin. There could be something amiss with the current bobbin--could be nicked or could even be the wrong bobbin for the machine. Also, make sure the bobbin is loaded and turning the correct direction in the machine.

Set the upper tension to the midway point. This is usually the starting point, although it will probably require some tweaking. Test your stitch and adjust the tension so the upper and bobbin threads meet in the middle of the fabric. Neither thread should dominate one side of the fabric or the other.

Understanding Thread Tension Threads

Last thing to try is a different presser foot.

If you still have the intermittent loop, you might want to take it for service. Could be a problem within the tension disk.

If the thread problem appears under the fabric, it is a top thread issue.

If the thread problem appears on the top of the fabric, the bobbin thread is the issue.

Perhaps the upper thread is not seated completely in the tension disk. Remove the upper thread from the machine, ALWAYS RAISE the presser foot, then rethread from the beginning. Make sure the thread path is correct. Test your stitch.

If the thread is still looping under the fabric, the upper tension is too loose. Set the upper tension to the midway point. Test and adjust the tension until it is where you want it. Preferred tension is when both threads meet in the middle of the fabric.

sewing machine tension Google Search


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increase the thread tension of the needle thread
this is an indication that the tension is not enough to pull the bobbin thread up tight

Can you provide more information on what type of sewing machine you have? Brand and Model would help. Thanks.

if your saying that your bobbin thread is balling up under the platen plate , this is a sure sign that your top thread tension is not correct and there isn't enough tension to pull the bobbin thread up from below

Sounds like "thread nesting" also called "bird nesting." Usually, it is a result of incorrect threading, incorrect tension, or the thread not being properly seated in the tension disk.

Remove the thread.
Install a brand new needle.
RAISE the presser foot and rethread the machine from the beginning making sure the thread path is correct.
Set the upper tension to the midway point between low & high numbers.
Test.
The correct tension is achieved when the upper and bobbin threads meet in the middle of the fabric. If upper thread is looping under the fabric, the upper tension is too loose. If the bobbin thread is appearing on the top of the fabric, the upper tension is too tight. If it is difficult to determine what is happening with tension, try using a different color thread (but ALWAYS the same type & weight) in the bobbin as what is used as upper thread.

Tension is static--it needs to be adjusted whenever a new project is begun because the needle/thread/fabric combination will affect the tension. A sewist should become comfortable with adjusting the upper tension on a piece of the scrap fabric before actually beginning to sew the project.

The needle/thread/fabric need to be compatible to get the best result. All About Needles

Sewing Machine Thread Bunching Up Here Why

http://www.chholderby.com/tips-tricks-and-help/part-4-bird-nesting

check the video
https://www.youtube.com/watch?v=LEaJxFRis9o

Remove the upper thread from your machine.

RAISE the presser foot and then rethread from the beginning. Raising the presser foot releases the tension disk so the thread will seat properly). Also, verify that the threading steps are correct (consult the threading instructions).

Check that the bobbin thread has been loaded in the bobbin case properly and threaded through the tension spring.

Test. If the upper thread is still showing under the fabric, tighten the upper tension disk until the upper and bobbin threads meet in the middle of the fabric.

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Loops appear on the surface (top side) of the fabric?
Reduce the tension by turning the upper tension control dial to a lower number. If the loops still appear on the surface of the fabric after you adjust the upper tension, the bobbin thread may be too loose. In this case, turn the screw clockwise, being careful not to over-tighten the screw, approximately 30-45 degrees to increase bobbin tension. After you adjust the bobbin thread, adjust the upper thread to match the bobbin thread.
Make sure you reset before your next project.

Bottom looping says upper tension problems (too loose). Rethread it making sure the presser foot is up so the thread is inbetween the tension discs.