First I make some wood blocks with 15 degree cuts on the ends. The ring is an example of the desired end result - a segmented rosette (although this one is made from scrap to practice)
I also made a little jig to hold the blocks while I bandsaw the blocks into little windows.
I use double sided tape to hold down the windows so I can get them the same thinness with a thinness sander. Some people call these machines thickness sanders, but mine makes stuff thinner, not thicker.
The little windows are assembled into panels with purflings in between. The inside diameter must be bigger than the sound hole of the guitar.
I will then use a little router to cut a round piece out of the assembled panels after I have saturated the joints with thin CA glue to stick the whole thing together. The strange-shaped window will go under the neck so it won't show. You can leave the ring open there, but I like to have a whole complete ring - it is easier to handle.
