These are experimental simplified versions of the guide bearings for all three axis on a Mendel type printer. They are NOT direct replacements and will require other modifications to work.
These are a part of my Mendel/Huxley "remix" currently code named "Mindel" (for MINimal MenDEL) (UPDATE 11/26/10 - project renamed "Integrated Parametric RepRap"). These are not ready for prime time but I am releasing them now in the spirit of "release early, release often."
Follow the progress at http://reprap.org/wiki/Integrated_Parametric_RepRap