That diagonally laminated binding around the top edge of my ukuleles is called “rope” binding. You can see it on the fancier models of old Hawaiian ukuleles. At first appearance it is a nice “old school” decorative touch, but it is much more important than that.
I first saw it done in alternating pearl and ebony on very lightly built Neopolitan mandolins. Also on Latin American instruments – vihuelas, bajo sextos, mariachi basses etc. You can see great examples of it on the Ukulele Hall OF Fame’s excellent website. (see the Links page)
The first modern use of it I saw was in Bob Brozman’s Bear Creek Kona model guitar a few years ago. I figured out a way of making it by laminating poplar and rosewood strips and bounced my idea off Bill Hardin of Bear Creek Guitars. He was very helpful. I am forever grateful.
The principle behind rope binding is as old as wooden soundboards on stringed instruments. It protects the edge of the top from splitting and from knocks, and loosens up the edge of the soundboard to enchance vibration. That line of purfling around the edge of a violin sits right over the edge of the interior lining where the soundboard “hinges”. All the fancy abalone and purfling around the edge of expensive steel string guitars does the same thing. It is expensive and time consuming to do, but the reward is a better sounding instrument.
So… rope binding provides a flexible, shock absorbing chain of little diagonal grained patches which cross all the glue joints around the top of the ukulele. You can see a cross section of it below. Apart from all that I like the way it looks. In case you don’t like it, any of my ukuleles can be ordered with plain maple or rosewood binding.