My top stitch is flat, but the bobbin is bunching and looping extra thread. cotton fabric, polyester thread

Check you tension if bottom thread loopy it's the spool try re threading machine. And change the needle

You are getting a thread mess under the fabric? Frequently, this occurs because the top thread is not fully seated in the tension disk.

Install a brand new needle.
Remove the top thread from the machine.
ALWAYS RAISE the presser foot and rethread the machine from the beginning.
If necessary, adjust the top tension so the top and bobbin threads meet in the middle of the fabric.

Sewing Machine Thread Bunching Up Here Why

Birds nest under the fabric big loops of thread top side looks good...

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I am not sure as to your machine, are you saying a "brother" machine? If your tension is set, say on 6 and it is too tight, turn the dial one more number......to a 7 or to a five and then check again. Also, I would rethread the machine and also take the bobbin out and then put it back into the machine. A lot of times, the bobbin isn't threaded into the machine correctly and it bunches up. Also, you can't use certain thick thread on some machines.

That is called thread nesting or bird nesting--or what I like to call thread "barfs."

Be sure to ALWAYS RAISE the presser foot when threading the top thread. This releases the tension disk so the thread will seat completely.

Bring the bobbin thread to the top of the fabric and gently hold both thread tails in your left hand while taking the first stitch or two. It may be beneficial to manually turn the handwheel for the first couple of stitches. It also helps to have the take-up lever at it's highest point BEFORE starting to stitch.

Birds nest under the fabric big loops of thread top side looks good...

Sewing Machine Thread Bunching Up Here Why

What causes Bird Nests Superior Threads

How and Why to Bring up the Bobbin Thread

1. I believe that your bobbin tension is too tight.
2. Your top tension should be at about four.
3. When you do your top threading check the tension before threading the needle. It should have some tension but it can't be too loose. Do this with the foot down.
4. If you have adjusted the bobbin more loosely replace it and turn the hand wheel with some fabric in place. It should come out with a nice stitch. You may have to do very small adjustments to the top tension to make the stitch perfect.

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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Make sure you are using a brand-new needle and that is installed with the flat side facing the correct direction.

Remove the upper thread from the machine. ALWAYS RAISE the presser foot and rethread the upper thread. Verify the thread path is correct. Set the thread tension at the midway point between high & low number.

Lower the presser foot, retest the stitch quality on scrap fabric and adjust the upper thread tension until the upper thread and bobbin thread meet in the middle of the fabric.

Sewing Machine Thread Bunching Up Here Why

Understanding Thread Tension Threads

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First, try a brand new needle.

Second, consider using a better quality thread. By all means, AVOID old or bargain bin threads. Coats & Clark used to be a standard, but thread quality has improved over the past few years, so you may want to check out other brands like Aurafil, Superior, Isacord, etc. Also, cotton wrapped polyester thread releases thread lint that contributes to build-up of gunk in the machine. Some sewists have noted that they experience more sewing issues when using C&C threads. However, some machines will do better with certain thread brands than others, so some experimentation may be beneficial.

Third, check the stitch on your sample again. Generally, when thread loops appear on the underside of the fabric, it is the upper thread that is the problem. If loopy threads appear on the top of the fabric, it is the bobbin thread that is the issue. You can even use a different color in the top to help distinguish which thread is the problem.

Fourth, when threading the upper thread, Always Raise the Presser Foot during the threading process so the tension disk is released and the thread can seat properly. "Bird nesting" occurs when the thread is not seated in the tension disk.
Sewing Machine Thread Bunching Up Here Why

Birds nest under the fabric big loops of thread top side looks good...

Fifth, when the upper thread appears on the underside of the fabric, the upper thread tension is too loose. If the bobbin thread appears on the top of the fabric, the tension thread is too tight (or the bobbin thread is loose). Start out with the upper tension set at the midway point and tweak it from that point. The tension is ideal when both upper and bobbin threads meet in the middle of the fabric.

Also, remember that tension is not static--a tension setting for chiffon will most likely not work on cotton or denim. Get comfortable adjusting the tension to suit the project you are sewing.

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You didn't explain the symptoms. Is the thread bunching, looping, knotting under the fabric? Is the bobbin thread rising to the top of the fabric?

If it is bunching under the fabric, it is probably what is called thread nesting or bird nesting. There are several fixes, sometimes more than one fix is required to resolve the issue.

Be sure to clean under the needle plate, around the bobbin, and the feed dogs. If the machine has instructions for oiling, follow the directions using a fresh, good quality sewing machine oil and apply only 1-2 drops each spot.

Install a brand new needle. Make sure you are using a needle compatible with the thread and fabric being used. All About Needles
Best practice is to use the same thread in both the upper and bobbin. Also, avoid old or bargain bin thread. Spend an extra couple of dollars to reduce frustration and increase success with your machine. If you wish, you may use two different colors of thread to test so you can easily determine what is happening with the tension.

Remove the thread from the machine. RAISE the presser foot and rethread from the beginning--the thread needs to be seated firmly in the tension disk. Verify that the correct thread path is followed (consult the owner's manual).

Set the upper tension to the midway point between high & low numbers (this is the factory standard and is a good place to start, but every machine is different and may need adjustment).

Confirm that the bobbin is installed in the bobbin case (turning the correct direction) and that the bobbin case is threaded properly.

Before beginning to stitch, hand rotate the handwheel one rotation and pull the bobbin thread to the top of the fabric. Then, gently hold the thread tails in the left hand and slowly begin to stitch.

Test.

If thread is bunching, looping under the fabric, the upper tension is too loose. Tighten it and retest. On most machines, the lower the tension number, the looser the tension.

If the bobbin thread is rising to the top of the fabric, the upper tension is too tight. Loosen the upper tension and retest.

Keep adjusting and testing until it is where you want it. Generally, tension is correct when both threads (upper & bobbin) meet in the middle of the fabric. FWIW, tension is static and should be tested and readjusted every time a new project is begun. The needle, thread, and fabric will affect the tension, so it is important to get comfortable adjusting the tension.

Also found the following reviews. Appears that some users have had tension issues with their CG550.

Amazon com Customer Reviews Singer CG 550 10 Stitch Commercial Grade...

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Is it really the bobbin thread that is bunching under the fabric, or is it really the top thread that is creating loops and "bird nests" under the fabric???

Rethread your upper thread. BEFORE you thread the upper thread, be sure to RAISE the presser foot. This releases the upper thread tension disks so the thread is firmly seated in the tension disk.

If it continues to be a problem, then the upper tension needs to be tightened. Adjust slightly, then test. Repeat until the upper and lower threads meet in the middle of the fabric.

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