Due to the small size of the Proxxon MF70 mill there are no "off-the-shelf" rotary drive units to add a 4th axis capability.  This project demonstrates  a "scratch" built rotary drive unit using  available components.

"Indoor flyer" once again demonstrates that  there is no reason why more advanced  use of CNC methods needs to cost a great deal of money.  Follow the link at the top of the page to an example real use of this 4th axis unit .  The Gcode used to create components is derived via CNC toolkit, a good example of a  real world solution using minimum cost methods.   Click on the image to access the project details.