Miranda breaks it down here: https://www.youtube.com/watch?v=mmd_7p62Z18 Samba Reggae 1
Samba Reggae 1: BSD: .. . . . . . . . . . . . . . . . L // Order of the shaft hole, allowing to create a D-shaped hole, set this to zero. // Diameter of the knob. TaperPercentage = 20; // // Whether to create cutouts.