I have one, hate it , but love it! Two things.. You either have to guide it with your finger as it winds ,or take off the the full bobbin, and put it where the spool of thread was and re- wind it again on an empty bobbin again... Then it will be even. Here all of this time ( two years) it was ME! I do it so fast anymore that I don't even give it a thought ..I just do it. I don't see any tension button on it..just seems to wind it uneven if you just it the button to let it do it's own thing, try guiding it with your finger as it winds on it,that should do the trick! Good Luck!