Updated: Feb 01, 2017
I made the distance between the cut for the screw wider to allow a tighter pinch.
I also added a little catch rim on the inner hoop.
Wife could not find a hoop that didn't have a deep groove in it. so I made her this.
if you print really course (3.2+ mm layer height) you get a good gripping surface for the material.
I actually printed this before I posted to test and it works well.