Another question Donna - I am machine quilting this with the walking foot. I noticed that at times my stitch length varied. Then I noticed that it was like the quilt was catching on something. At first I thought it was something on the top, but then I discovered it was the threads from the bobbin on the underside. I cut the threads on the top when I move from block to block, but not on the bottom. I took the quilt out and turned it over now and trimmed all the threads before I go back to quilting. There's no wrinkles, but what should I be doing to resolve the other problem?