Hmmm....My take up roller has one half of a zipper set. It has the zipper pull at the left end.
My front roller has the other half of a zipper set, the slide in part.
ON THE QUILT BACK, with the back upside down (so that the batting will rest on the wrong side of the fabric) For the take up roller edge, I sew on a zipper that has a slide on the left end that will be zipped onto the take up roller.
One the front roller, I sew on a zipper with a zipper pull on the left end.
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I have two rollers at the front, one for the backing fabric, and one for the top. I also sew a zipper half just like the bottom of the back.
Hopefully the picture will help this make sense. I made this sample for me to use so that I get the right zipper in the right place. I just purchased much shorter zippers to make my sample.