Originally Posted by MamaHen
First off, what machine are you talking about. A home machine or a longarm? I'm guess your home machine because of your needle type & size. Have your tried a topstitch needle? For King Tut a Topstitch #90/14 It has a slightly bigger eye and longer grove for your thread, so less tension all ways. Double check to make sure that your bobbin thread is in correctly, I have found that many of the ladies don't know that the thread should come off the bobbin counter clockwise. It looks like to me that your top tension may be off a bit. Make yourself a small quilt sandwich with the exact fabrics you are using now, and try again with needle change. Then try a different bobbin thread, maybe the difference in the King Tut and bottom line is too much. Just some suggestions. Good luck.
My machine is a Bernina 820. There's only one way you can put the bobbin in as it's marked with sensors on one side that have to face out. You run the thread through the side slit and back to the thread cutter. I'm 99% certain it's threaded correctly.
I have my husband bringing me home some topstitching needles in the 90/14 size. I had my top tension lowered some but it was pulling through a lot on the back. Lowered the bobbin tension and raised the top a little. Other than the birds nests it looks like the tension is okay. Should I try raising the top tension a little more still?
I'll have to get through with the Bottom Line for now because I really don't want two different threads on the back. It's a plain white back and I'm worried two different threads, even though the same color, would be obvious. But maybe I'll put some regular cotton Mettler in the bobbin and see if that looks okay and acts better. I suppose a slight thread change is better than tangles all over.