Nice idea for light CNC work, not so sure about more intense jobs. The author did the conversion for $30. If you have an old 3D printer you could do this, but keep in mind the motors, drive (belt) may not be built to handle moving a dremel thru an object. Also you may not beable to re-use the controller for the motors in all cases.
https://www.instructables.com/Old-3d-Printer-Into-a-CNC-for-Under-30/