I've used Coats and Clarks for sewing for years, but this weekend I was stitching on my most recent D9P and the upper thread kept breaking.. about the 3rd time I started checking
the broken end only to find a little "knot" at each break..
looks like there was a "slub" in the thread that would not go through the needle eye. Very disappointed. Changed to a spool of Mettler and had no more problems.