I don't have a Grand Quilter but I have a 20 year old Design a quilt machine and I was ready to throw it out. Every thing I did seemed to make the thread break. I found a small bur on my throat plate will really cause a lot of grief. As I said my machine is old but you will learn all the quirks of it and love it later. I do use poly thread and it seems to do really good for years of washing , loving and dragging around by babies and adults.