Originally Posted by DogHouseMom

I have a 6600 - and I guess they are similar machines. When I first got it I thought the machine was very finicky because it didn't like different threads in top and bottom - whether piecing or quilting. But over time, getting used to the machine I guess, I no longer have the problem.

I'm getting ready to quilt a landscape quilt and it will have lots of different patterns and thread panting - so I'm making lots of practice sandwiches. My first choice of thread was a 50 wt connecting threads "essential" with a Gutterman 60 wt in the bobbin. I've got the tension worked out - 8 - YES 8!!

so you are free motion quilting at an 8? what happens when you don't get tension? does it catch on the bottom?

So .. ignore the books and whatever anyone else tells you. Keep working out the tension as YOU sew. The tension is just as dependent on the speed of the machine and your hand speed as it is on the type of needle, thread choice, and fabric used.

And yes. Clean out the machine completely :)