Kiri, straight woodwinds, like the muto, are not made by step drilling and sanding. They may be step drilled as a preliminary step to remove excessive waist and save wear on your tools. Then they are reamed out. Traditionally, they are reamed with relatively straight tapered reamers and then bore tuned with supplemental reamers, the same way fine oboes are still made. Depending upon the diameter of the bore, tolerances as fine as 0.1mm may be critical for the tuning of individual notes / harmonics at nodal and anti-nodal points, and this is what the builder is after with the supplemental reamers. Today, many people replicating early instruments build eccentrically tapered reamers to include the "original" bore details and do it in one pass. Easy with a CNC grinding machine. Not so easy with a hammer, swage block and anvil. If you have questions, you might try talking to Joel. He and I built a few cornetti in the days when I was super of the Levin shop, and of course he builds shawms, too. And the proper term for the decorative stamping is "blind tooling". What most people call tooled leather is not. That's carving and stamping. This is. It is done with hot brass tools. If the impressions are filled with gold leaf, it is plain "tooling". The blind refers to the fact it is not filled. Same as on fine book bindings. Now, ivory cuervos present a different set of problems, and were probably built by specialists with highly specialized tools. I have some thoughts on how they did it, but nothing definite. It only took me 20 years to figure out how they made the reamers to adequate precision in a blacksmith's forge.
Do you know where to find technical drawings with measurements and sizes? I found some, but none of them specify the dimensions of the bores, both diameter and their locations on the instrument. I want to build one.
