In the movie Harvey the main character could see a giant rabbit named Harvey. Other's thought he was nuts!  The Pooka 4th Axis falls into that same catagory.  In CNC there is a X, Y and Z axis. Then why are there boards that will drive a fourth axis?  Some people use the X and W together to drive a gantry style mill.  In fact there are Rotory tables out there. They rotate the piece as it is machined.  On older machines the Y or X axis could be disconnected in order to run the rotory table. Some people call this the Fourth axis. A rotory table costs any between $800 and $5,000.  What are they used for?  Cutting gears and making items like chess pieces.  Nobody talks about building a rotory table.  I did see one once made out of plexi-glass. It was belt driven.  Someone was trying to sell it for $300.
         Ok here is the deal. I designed a cheap 4th axis. The table will uses a set of gears from Boston Gear.  Local Boston Gear dealers will let you buy them with just a credit card.  The table won't do every angle the $800 dollar ones will. It won't have the power either.  The unit uses a Worm gear so backlash won't be too bad.  Basically this design will be for screwing around!  This unit is for the advanced experimentor-programmer.
          My design is very easy to build.  I include a diagram for a step/direction circuit just in case you don't have a four axis controller.  This unit can be driven by the Piker 1X controller off  the connector of your 3 axis controller.
          The output shaft moves .0045 degees  with each step of the motor.  This unit can be built for under  $75.00 US.  The plans will show how to build the unit in the picture.  Two gears, a floppy drive stepping motor and some PVC and you have a simple 4th axis.  Nobody has this!!!  I want $23 which includes free shipping and handling.  I only sell and ship US and Canada.