Or it could just be the blue thread from Star. I had recently bought the blue and the pink. The fabric was a little bit different that I sewed these 2 colors on. But the thread when I pulled on it would break and fray. I don't think it was the machine. I think the thread was bad. My other color thread did fine and didn't break on the machine. I'll be checking them out, but think I will be using this thread for something else, lol.