ZFeet - adjustable z-axis supports for RepRap

This thing is a support for the z-axis smooth rods of the Prusa Mendel. Supporting the bottom side of the z-axis reduces the side-to-side wobble of the machine and produces surprisingly improved prints. In the image of the large print (part of http://www.thingiverse.com/thing:10526), I placed supports under the smooth rods about 3/4 of the way through the print, you can see the dramatic improvement.

The design uses M6 nuts and bolts to make the support adjustable. Using M6 x 18mm bolts, the f