Wowzer!
All I can say about this is ,
"Where have you been all my life!"
I managed to bind four bed size quilts in
one day using this foot.
This technique is used when the
binding is sewn to the back of the quilt
and then folded over onto the front.
It manages to keep the stitching exactly
placed on my binding
and lets me speed along, stress free.
Here is how it works.
The guide that is in the middle and is
usually placed in the " ditch or seam"
for quilting is used as a
guide for the edge of the binding .
Set the needle position to right of the binding edge
as desired and then
top stitch the binding in place.
This foot is called a "Stitch in the ditch foot"
You should easily be able to find this foot
at any sewing machine store or supplier.
You may even find this in you sewing
machine tool box!