The person sewing with this machine got some thread wound around the bobbin and consequently the hook and needle adjustment came out of alignment. How do I rest it? The hook is probably where the problem lies. Subsequent to this event she had someone try to correct the timing by adjusting the needle bar. Uh Oh. One more question. What is the correct needle length ( size ) for this machine. No point trying to set timing with my Juki needle if it's the wrong size.