I am one of the unfortunates whose original-style z-rod lowers both delaminted at original assembly time. I repaired them, and they have been fine, but it has been in the back of my head to work up a re-design... then AO released : http://www.thingiverse.com/thing:15861 This piece incorporates everything I had in mind... except that Thing was designed to use 608 bearings. I have the "original" thrust bearings for z-motor load reduction, so I derived this version implementing the hole sizes from maxbots' original piece.Same instructions from the AlephObjects version... you'll need a couple of additional t-nuts in the upper y-axis (side) frame extrusion on each side.I added a support layer to the rod hole area which needs to be cleaned out before use.I also added and "on edge" version of the smooth rod clamp for anyone who might prefer printing it that way "for strength" (I haven't seen any problem with those I have which are printed flat, but...)Z-clamps can use M5 x 20mm screws