I have Janome 1600P and when I begin quilting I get a thread ball at the bottom of the quilt. Occ it knots so badly it won't move and I have to crawl under to get the bobbin out and begin cutting threads to resolve the gunoidulum.
Anybody have thoughts on WHY????????????????????
I HAVE OILED, CHANGED NEEDLES, ADJUSTED TENSION BOTH BOBBIN AND UPPER.
HELP ILLSA

I know from this post your frustrated and I am not trying to make things worse I just read an article about this issue and these are the things she said might be the cause. Are you using the same thread for the bobbin as in the top? do you use a bobbin genie a little disc for the bobbin?

Are you pulling the bobbin thread to the top before you start quilting? Hang on to both threads until you get it anchored. You can use different threads in top and bottom, as long as your tension is balanced.

Many people forget to do this. Also, be sure your presser foot is down. This might be auto, I am not sure. I do know that on the older Husq. machines it would make a mess if you forgot. Good luck!

I am interested in this topic too... I have a HandiQuilter and the same thing happened to me (also a Janome 1600P). It seems I remember from a previous topic that this Janome model is picky about the kind of thread. I spent quite a while looking at threads online today. The Superior thread site said that problems like this are often mismatched thread size and needle size. I am going to try another brand of thread when I get another top ready to quilt. The last one is sitting on the shelf because I need to remove all the stitching since I have all those bird's nests on the back.

Will be interested to see what everyone has to say.

Yes I have the same thread. Don't know what a bobbin genie is. Thanks for answering. Illsa

Yes I am. Sometimes when you use the auto thread cut you don't have to pull it to top if you haven't broken the thread.
Thanks for answering.

The Janome rep that sold the machine sold me Signature Machine Quilting 100% Cotton thread.
He also sold me the wrong needles but I have the correct needles now.

Sometimes I can ignore the thread balls and continue sewing and the stitches are perfect for a long time like one row of 86" quilt before it shreds the thread or breaks the thread. Completely baffles and frustrates me when it can work perfect then screw up. Machines aren't supposed to do that I didn't think.

Bobbin genie is a plastic type washer you put in your bobbin that helps keep the thread from making nest. Like I said I just read this yesterday on another site. So sorry this this frustrating hang in there.