Blocks for oil less bronze bearing bush for Prusa I3

Blocks for oil less bronze bearing bush (as JDB 081225).
length=25mm external diameter=12mm internal diameter=8mm
Made to replace 8mm linear ball bearing like SCS8UU (use same holes).
It result to be quieter and more rigid.
Test at 120mm/s http://youtu.be/xSBDmkCVQCw

Please note that blocks externals dimensions are a little differents than SCS8UU blocks (Shorter and a little thicker)
Based on this idea http://www.thingiverse.com/thing:97041