I have found its funny about threads and some work and some don't! I have found Aurifil works the best for piecing and most other sewing, not much lint either. Lots of problems goes to user error. I have had mine about 2 yrs now and finely got it to run great! I use Isacord for embroidery too. Just don't sew too fast and all thread breaks now and then. Check you tension too might be too tight!