Check out this GIF...
Sewing machine..
Zipper
Last edited by Kelly_Bramble; 11-27-2016 at 07:40 PM.
I am OK with the tumbler and the zipper but something is just not right with the sewing machine because if you watch closely it is magically passing one side of the top thread loop through the bobbin thread. If you want to see the real bobbin action go to the below website for a similar but importantly different animation.
http://sewingschool.org/2010/11/04/how-a-bobbin-works/