One other thing that noone else has mentioned is the batting and the thread. What kind of batting are you using and what kind of thread? If you are using a batting that has a scrim or any amount of polyester batting and using a cotton thread you will have a nightmare. The poly batting acts like sandpaper on the thread and causes it to shred and break. Also if you have eyelash problems on the back are they on the curves only or even when you go straight? If they are only on the curves slow down on the curves. It is like driving around a hairpin curve with your car you want to slow down. Also if you are changing directions you will want to stop and hover for a second or two. You will find that you will have improved stitch quality over all.