The bobbin thread can easily slip over to the right, when you see that you will have the thread mess on the bottom of your quilt. I always look at the bobbin and make sure that the thread has clicked in and stays to the left. I like Aurifill and Superior, they both work well. My quilt shop says Coats and Clark will mess up a machine. That use to be my go to thread for 40 years.
Originally Posted by
Raggiemom
Not to be insulting, but are you sure it's threaded correctly? Several times I thought I had mine done right, but when I looked, the thread had slipped off the upper thread tension control. Also, like others have said, my 6600 is VERY picky about thread. I generally use Aurifil in it. Hope you're able to figure out the problem, it is a great machine when operating smoothly.