Remove the top board from the jig, wedges first then clamps. Draw the shape on with the template again and then cut round with the bandsaw. When finished, spray with sanding sealer around the soundhole / rosette area – this will help to keep the edges crisp and neat when we come to route for the rosette later.
Hold a metal ruler down one side of the centre-seam strips and then plane at an angle to create a facet. Follow this up with rough sandpaper. Turn the board round and repeat on the other side.
Using sandpaper in increasing grits stuck to a credit card (one side 120, the other 240 grit), sand the strip so that there are no facets anymore, just a rounded surface.
Put a setsquare against the strips and use it to place the cross-braces at 90 degrees to the centre where the lines were marked previously. Mark the sides of the cross brace onto the centre seam strips so we know where to cut.
Use a small saw to cut inside the lines so the cross-braces *nearly* fit into the gaps – use a file to get them snugly in. The fit should be snug enough to be able to place a brace in and then lift the whole back with it.
Using the 15′ radius dish, glue the braces in (also radiused to 15′) and wedge them using any method you like. Don’t forget to glue the ends of the centre-seam strips as well. You should see glue coming out of both sides of the braces once wedged.
Using a rough template for a rosette piece, cut out rough radiused pieces using the bandsaw. Mark the angle they need to be cut at (ruler from the centre pin at both ends), make one piece and then use it as a template to make others. Fit them on to the router board; the last one will be shorter and there should be a gap left i.e. not tight-fitting. This piece will be covered by the fingerboard anyway.
Use the Dremel router on a pin to route the inside of the rosette and then the outside. Measurement-wise, the sound hole has a 4″ diameter and then you need to leave 1/8 -> 3/16 until the rosette. The rosette can be as thick as desired.