[FreeRider] had built a CNC router before but it was big ... Skate bearings support 5/16″ threaded rod used as lead screws. Lead nuts are tapped HDPE blocks and seem to be doing a satisfactory ...

Non-cardboard parts include threaded rod for the lead screws ... and it’s perfectly capable of teaching all the basics of CNC builds to a beginner, which is a key design goal.