Someone please help me. I only machine quilt. I use the walking foot. I can do backing fine on potholders, place mats and table runners but anything bigger than that and I get creases in the back. I am always pulling out. It is never smooth. I pin and pin and pin so I don't know what I am doing wrong. Is the only solution to keep cutting the thread, taking a look underneath and then reconnecting thread? That doesn't seem practical.