For piecing I use Mettler (100% cotton, silk finish) right now but am trying out Masterpiece by Superior Threads as soon as it comes in the mail. For my bobbin I use Bottom Line, by ST's as well. For quilting I've used the Mettler thread I used for piecing but then I started using King Tut and love it's thicker weight. The quilting stands out more and I love all the varigated color choices King Tut has. My machine didn't have any trouble with it.