I have an older Singer Quantum and it doesn't matter if I use black thread on top and white thread in bobbin. You can't see any pokies at all. It sews a perfect straight stitch. My other machines I have, a Bernina, Brother, other vintage Singers (includig Featherweight) and Janome do not have this perfect stitch. I guess what I'm saying is if Singer got it right with one model of machine why can't the 'best' machines for quilting get it right too.