I also thank myself for saving all these strange and curious items that came my way when I bought the sewing machine. I have two Elnas that are nearly identical. The second one I bought at an "estate sale store" and it came with a nice collection of items that I thought I might perhaps find useful someday.
For the record, the darning foot is also known as a "free motion" foot or an "embroidery foot".
A trial run with the setup using a scrap of fabric was encouraging. It all works just fine. The foot has a spring loaded lever that rides against the needle shaft and raises the foot each time the needle goes up. I should be able to duplicate the work exhibited in the above video quite nicely with this setup.
Tom's home page / tom@mmto.org