The rotary axis, which can be printed on a 3D printer, is not a serious tool, since plastic cams cannot provide a strong grip on the part. But such a design can be a teaching aid, an interesting designer, or serve to perform light work, for example, for laser engraving. A stepper motor allows this design to be used as a dividing head. The parts are designed to be printed on an FDM 3D printer without support. But in addition to the parts presented here, you will need 2 bearings measuring 42 x 20 x 12 mm, a NEMA 17 stepper motor with a 5 mm shaft, and two dozen 3 x 6 mm screws.The chuck is self-centering, outer diameter 40 mm, inner hole 16 mm, has straight and reverse jaws, can clamp workpieces up to 36 mm in diameter. It can be installed both on the engine side and on the opposite side. Mechanical transmission has 2 steps. They are switched by a fungus located opposite the engine. Switching must be carried out with the machine stopped. You can print the body walls in the same way as other parts, but it is better to make them from a transparent material in order to observe the operation of the mechanism.