I bought this b4 I moved to Chile and LOVE it. Compared the others b4 I bought and this is the best IMO. (I had to know it was heavy duty and wouldn't cause trouble 4,000 miles away from it's home turf.)
http://theeasywinder.com/
Straight from a guy who was a tech on machines his whole life. Have both an HQ 16 LA that takes bigger commercial bobbins, had a Phaff, Brother,Singer and now overseas here on 220V I have a Janome as well. This works on them all smoothly and accurately. Love it. Takes AA batteries which last forever and means there is no cord to drag around and find a home for.