Here's my personal jig for making strings.
About 8 years ago, I had the opportunity to purchase a dozen or so raw boards, all twins of this one for $15 each.
I was traveling down the Oregon coast and stopped at one of those roadside wood places that sells carving and such. In a dusty corner was about a dozen of these nicely figured planks. Three quarters thick with a live edge on both sides. I didn't know what I'd do with them, but knew I liked them, so I bought two. They sat in my shop for a few years until I walked in one day looking to make my first jig. Presto!