long stitches on back
 

My stitches on the front look fine but I cannot get the tension right so that the back stitches look good. This problem started yesterday. Before that, everything was fine.
I have done all the obvious things...fiddled with the tension on top and also the bobbin tension, changed needles a couple of times, cleaned and the machine, changed thread etc. I thought it may have been the bobbin thread because I had just wound a new bobbin of thread and inserted it. I wound another bobbin but the problem is still there. The stitches are long and too loose. Can anyone advise on something else I can try?
Thanks for reading. Hope someone can give me a fix for this problem, A trip to the repair shop is not in my budget right now.

Are you talking about FMQ or straight line quilting? I found that my machines like the feed dogs up on FMQ. I don't cover them and I set the stitch length to zero. Has something to do with the tension. Just a thought.

What machine are you using? Have you checked the owner's manual about it?

Do you have bobbin case or drop in bobbin? Sounds to me like the bobbin might not be seated correctly. Definitely has to do with the bobbin.

Mine has done that when the bobbin is put in the case backwards. (Thread unwinding the wrong direction)

I am doing piecing..making some 9-patch blocks. I have a small Brother machine. I've had it for years. It is a real workhorse. The bobbin is the type that you put into a case before inserting it into the machine. The owner's manual just says to adjust the tension but that's not working. The bobbin is in correctly...same way I've always put it in and acc. to the manual, it's in the correct way. I am at my wit's end, trying to figure out what is happening.

Could you post a picture?

When you say you're adjusting the tension, do you mean you tried adjusting the top tension, the bobbin tension, or both?

can you send a pic? you say the bottom stitches are long--are they loose? If so the top tension likely needs adjusting. First, unthread and totally rethread the top--making sure you are going through all the tension spots (especially make sure the take up arm is pulling the thread through the check spring of the tensioner). If that is ok, get some scrap fabric and start sewing, adjusting the top tension as you do. That sounds like where you are having issues. It could be your check spring needs replacing--when is last time you had maintenance done?.

If you have changed your bobbin tension, you may want to eae it back to what it was originally so that the tension adjustments on top will work. Problems on the bottom are almost always top tension; shredding thread or weird top stitches usually are bobbin issues. Good luck--nothing more frustrating!

If you have tension issues that appear on the bottom, it's often the top tension that's off. I'm wondering if you have a bit of fluff stuck in the tension disks which is keeping them from applying appropriate tension. use a sturdy thread to floss between them, and when you thread your machine make sure that the presser foot is up until the you've threaded the whole thing and are ready to put it thru the needle. when the foot is up, there is no tension on the disks so the thread can seat properly.

I changed tension gradually and kept notes of what showed on each side.I always do that when fiddling with tension. Thanks for all those that gave suggestions. It's so great to be able to ask questions and get lots of feedback.
My friend came last night and helped me. We tried all the suggestions offered here but it didn't help. I am going to use the next few days to do some cleanup in my sewing room and also work on my hand quilting project. I will have to take 'Dobbin' to the repair place at the end of January. Hope he just needs something minor.