I have a Pfaff Powerquilter 16.0 which is a midarm sit-down quilter. I had been fighting a batik quilt, having skipped stitches and breakage of the thread, while using 40wt cotton thread and a size 16 needle. I am now using a size 18 needle and she is quilting like butter. Batiks are a tighter weave, have wax residue and some dirt on them even tho you cannot see it. The size 18 gives the thread more room to glide thru the fabric. Hope this helps someone! I was about ready to pull my hair out!