An improved version of upper Z-axis bracket for Prusa I3 Hephestos.
Using ball bearing reduce swings of Z-axis jackscrew and improve printing precision.
You need two ball bearing 10x5x4 mm (outside diam. - inside diam. - height) or two 10x5x5.
Insert ball bearing in the biggest hole (help with a flat screwdriver into printed crack).
Mine printed with Cura: layer: 0.2mm - sheel 1.2mm - bottom/top thickness: 0.6mm - fill: 40%