Why is top thread tension too tight?

tensions are not an exact science but from your description of puckered which by the way is perfect indicates that the tension is way to high lower the tension settings and always use a practice sample first before going live on your project

indications of a bobbin tension incorrect is the bottom thread lies flat under the bottom material
it seldom needs adjusting but if you have to the spring plate that you pull the thread under as you put the bobbin back in the holder is where you adjust it
there is a small screw that holds that plate on so the slightest movement of the screw makes a lot of difference of the thread tension
all thread tension problems relate to the needle thread tension and if you have it set to 0 then the thread will be bunching up under the material
you don't say what the issues are but pounds to peanuts , it will be the top tension that is the problem
It will be correct when you are threading the needle , you pull the thread out first before threading and there is a resistance to pulling the thread

Usually, the upper tension should work in tandem with the bobbin tension so they actually pull against each other. If the upper tension is too loose, then the bobbin tension will not be pulled up into the fabric. Try tightening the upper tension and see if that makes a difference. The two threads should meet in the middle of the fabric.

However, on occasion, the bobbin tension is, in fact, too tight and can be adjusted. Be sure to mark the setting BEFORE making any adjustments (so you can reverse your changes) and make tiny incremental adjustments to the bobbin tension, ie 1/8 to 1/4 turn. A little adjustment makes a BIG change in bobbin tension.

Understanding Thread Tension Threads

1. Try to loosen the top tension first.
2. If this doesn't work remove the bobbin and tighten the bobbin.
3. The purpose of this is to have the top and bottom tension even. This is similar to a tug of war. Whichever way is stronger is where the knot will be going. You want the knot in the middle of the fabric.
4. Test your top tension by leaving the foot up. Pull the thread through back and forth. It should be easy. If it isn't you will need to adjust the tension mechanism.

There is a tension set document added to help you.

I would say your tension spring is shot on your tension assembly. replace it.

Check the threading and tension on the TOP thread through the needle. When you pull on the thread is there tension? Try increasing the tension as it is the top thread that you see effected on the bottom side of the seam. The best way to do this is to unthread the top side completely and rethread it again to make sure you have it threaded correctly, then check that top tension as I said above.

You can also check that the bobbin tension isn't too tight but it is most likely the top tension is too loose when it looks that way.

Recheck the tension on the top thread. Test it before you put it through the needle to see if there's any tension. It should pull but with some resistance. Also check the needle and make sure it is the right type for the fabric and not bent etc.

Looping on the underside of the stitch is from the upper thread, usually tension problem. But do check the bobbin tension and make sure it isn't too tight, though that's not usually the problem you're describing. The two tensions need to work together in order to get a nice, flat (not puckered or loopy) stitch.

One last thing you might check too, though again this wouldn't typically be the problem - is the dogfeed moving the material along under the presser foot correctly?

Most of the time the problem you're describing is due to not enough tension on the upper thread.

If I'm understanding the problem right it sounds like you have no tension on the bobbin. Take it out and see if the thread has any resistance when you pull it out. If you hold it up by thel thread and let it dangle and it just drops to the floor the tension isn't right. Check and make sure it is threaded correctly and tighten the tension. Test it again and when you dangle it, it should drop a bit with resistance when you hold it by the thread.

Also check that the top tension isn't too tight, but in this case it is more likely that the bobbin is too loose. And check to see if the dogfeed (the teeth that comes through the plate opening under the needle) is up and moving the material through the presser foot. If the material isn't moving at all it will sort of stitch "in one place" which will give you a bunch of threads all knotted up underneath. If those underneath threads are loopy that is a sign the bobbin thread is too loose (tension too loose)

Does the top thread tension reduce when you rotate the tension dial below 4 - if not, it is likely that the thread is getting caught either in the takeup arm or in the check spring. Make sure there are no trapped threads in the takeup arm (the bit that goes up-and-down through the slot in the front cover) and make sure that, as you're threading the machine, before you thread through the takeup arm that the thread runs smootly through the pre-tensioner at the back, through the tension discs next to the tension adjuster and through the bottom of the takeup arm cover before it returns back towards the top of the machine.

it sounds like your bobbin tension is too tight. to adjust bobbin tension, remove bobbin case (remove needle plate first) and adjust bobbin tension screw on side of case until bobbin thread has a slight resistance as you pull it through the bobbin case.

this will be trial and error until you get best result. you should always try and match top and bottom threads. if the top thread is quite thick you may have continue to increase needle thread tension until balanced.

scott