The drawing shows the inverted conical bore of recorders of the baroque period. The upper graph shows the head joint (TETE), the lower one the assembled middle (CORPS) and foot (PIED), showing a "half section view" with the diameter enlarged 20 times compared to the length.
The complexity of baroque recorders is in the bore, the aim being to enable musicians to play in tune, with agility and a beautiful sound, over a range of more than two octaves, using only eight holes. Each part of the bore acts on intonation, tone quality, quickness of speech, or more than one of these at the same time.
This type of bore is usually made using several different reamers.
The recorder shown here is the alto by Thomas Stanesby Junior in the Musée de la Musique, in Paris
Here is a section view of a copy of the same recorder, showing the actual shape and proportions of the bore.