I was using the wrong size needle for the thread I had for 2 1/2 years and complained about my sewing machine all the time. Finally I told my dealer I could only use 50 wt. Presencia cones and he took the thread I said I couldn't use and put in the right size needle and my machine just sewed perfectly fine. He said I needed a bigger needle for 40 wt. thread. So now I always make sure the thread and needle match. Makes all the difference! Use to clunk and clatter and thread would break before. Now it purrs!!