Making a quilt out of flannel, the thread keeps breaking. Did all the troubleshooting, whats wrong?

Not sure if you are piecing or trying to free motion quilt. If FMQ, try using an Embroidery needle (it has a groove in the shaft that helps protect the thread) or a Topstitch needle. Make sure the thread is not too thick for the needle's eye. Check to make sure the upper and lower tensions are not too tight. You might try changing brand/type of thread.

Here's a needle guide:
SCHMETZ Household Needle Chart

Or review suggestions for breaking thread here:
Why is my thread breaking

Hope this helps!

check the timing between the needle and rotating hook also check the teeth for possible lost of timing maybe low or high to much.

It sounds like the needleis not installed correctly, check the manual for the proper instructions.

I am guessing here because I don't know what kind of thread you are using but, I am guessing that you have something in the upper tension discs causing the thread to not have tension, first I would recommend if you can see in to the disc put the foot in the up position and and blow out the disc. If this doesn't work take it to you local dealer and have the tensions adjusted, also look at the needle plate and see if there are marks in the hole, if there are it would be wise to either clean them out or get a new needle plate they will severely affect free motion

you need to change your needle first. then if that does not work you may have a small area on your bobbin case that has been damaged

There is special thread for denim/jeans. It usually comes in shades of brown. It's a little heavier and might help with the breakage. You might also want to try a little less tension. I assume you already have a Schmetz denim needle?

Use a bigger spool stopper to keep the thread from catching in the **** on the thread spool.
sewman7

the needle thread tension is wrong
bunching up under the material indicates that it is too loose

Try a different thread. It may be old or dry. Even some new threads seem to be finicky.

Q1.(A) Without realising, you could be 'helping' the material feed.
Q2. (A) Is the thread collecting at the start or during sewing?,,if at the start, make sure threads are clear and hold them out the back of work gently till a few stictches are made.
If during sewing, it could be tension isn't adjusted correctly, experiment.