The first method is the double turn back method, where two rotation coordinates directly control the direction of the tool axis; The second one is the drooping rotation method, where the two coordinate axes are at the top of the cutter, but the rotation axis is not perpendicular to the linear axis;

The third one is the dual turntable method, where two rotation coordinates directly control spatial rotation; The fourth one is a hanging workbench, with two axes on the workbench, but the rotation axis is not perpendicular to that axis; The fifth one is a swing starting from one rotation, with two rotation coordinates on one tool and one on the workpiece.