I finally had the opportunity to spend a bit of time in the workshop again, so I spent an afternoon inlaying a rosette and cutting out the soundhole.
The rosette on a Baroque guitar is rather different than the fancy mosaic or otherwise highly figured rosette of a modern classical. The focus on Baroque guitars is the beautiful and intricate rose, while the rosette is a few simple lines.
(for clarification: the rosette is the decoration around the soundhole; the rose is the fancy bit of carving that fills the soundhole on early guitars and lutes).
For this process I use a circle cutter made by my father:
Logistics: first I drill a 1/8 inch hole at the centre of the soundhole, which fits the pin of the circle cutter. The circle cutter is adjusted to the correct radius. Then the pin of the circle cutter goes through the soundboard and into a workboard designed for the purpose. I work from the widest rosette ring to the soundhole. The blades have an angled cutting surface, so the flat side of the blade goes on the outside of the channel being cut.
For this guitar, I wanted 2 rings of thin black-white-black inlay, so I cut two 1.5 mm wide channels, one with a radius of about 49.5 mm, the other with a radius about 43 mm, two cuts each. Because these channels are so narrow, cleaning out between the edge cuts made by the circle cutter is a rather delicate operation. I do not have a chisel narrow enough, so I ended up using some small knife blades to do some initial wood removal by hand, and then finishing up with the wrong end of the circle-cutter blades. These blades are actually from a purfling cutter, and happen to be almost exactly the right thickness, so I put the blade in the circle cutter upside down, and ran it around the channel a few times. Not a method which I can easily describe, nor a method that I would ever recommend. However, it worked today.
I had ready-made black-white-black purfling strips, so the actual inlay work was quite simple. Cut the strip to length, apply glue, press into channel. Then clamp. Wait for an hour or so. Use a chisel very carefully to remove the excess purfling (when glued in it was proud of the surface about 1.5 mm). And voila! a beautiful and simple rosette.
With this done, I made the final circle cut for the soundhole, with a radius of 40 mm, this time actually cutting through the soundboard.
Next is the rose! This was probably the most exciting and enjoyable (and most time consuming) part for me on the last guitar, so I am looking forward to the process.