Needs a right hand winder (clockwise) so it goes in to the barrel with what looks like an anticlockwise wind (left hand wind), but because these barrels are flipped over once on the mainplate that then makes it the correct orientation.

 

Thanks GuyJ for your help.

 

Think there is a thread about mainspring winder already. For the 6309? You could use the same for the 6139.

http://www.thewatchsite.com/34-watchmaking-tinkering/255746-bergeon-mainspring-winder-07-update.html