So first I should say that this isn't my original idea, I first heard about it
here, and they have a few more pictures and instructions. But I wanted to share it with this forum now that I've tried it.
This is a guide to feed grosgrain ribbon into a machine, folded in half, to use to finish edges. No more uneven finishing, and it goes *way* faster. I finished four pannier seams and made back all the time I spent making this (about 10 minutes).
The plastic is from a box of spinach ($1 because it was a manager's special), and the tape I already had, so I'm not counting it in the cost. The original thread on hammock forums mentions a specific brand of double-sided tape, but I used what came with my Frost King window film package - I bought it to use the film as a ground cover, so I had an entire roll of the tape left over. It worked just fine and came off with very little residue.
I use 3/4" grosgrain, and I started out with a 2" wide piece of plastic, but that was far too big - I kept re-creasing it and cutting it down. The final dimensions came out 7/8" wide, with the two folded-over sections 1/4" wide. So I ended up using a 1 3/8" piece of plastic total.
I'm making enough gear now that I'll probably still buy the professional version, made of metal. But I thought this would be a cool thing to try out, and it works great!