Welcome to RepRap!
Thank you for posting your WatBot.
Is it possible to "use 4 axis's(1 slaved X axis+XYZ) with the reprap software"?
Apparently the prusajr is already driving his RepRap using XYZ plus another identical Z axis motor. As far as I can tell, he's using the standard Mendel RepRap software and Mendel RepRap electronics with no modifications. He mentions "two steppers wired in parallel to one driver" in a blog post. When I click the picture on the right sidebar of the Prusa Mendel page I see the Z stepper motors, one at the top-left and one at the top-right corners. The parts list on that page lists 5 stepper motors, 2 for Z plus one each for X Y Extruder.
Would that technique work for your WatBot?
p.s.: About a week ago I saw a model produced by an architect feeding topo map data into a CNC machine, then putting (thimble-sized) buildings on the resulting wooden landscape. I hope you make stuff that is just as fascinating. --DavidCary 03:24, 8 November 2010 (UTC)