This is a modified-upgraded version of Chopmeister's H3 extruder http://www.thingiverse.com/thing:27626It includes all the available upgrades, but the housing has been made to allow for a stable fixing of the necessary bearings and is compatible with the latest knurled bolt from ultimaker which allows for quick release.2 Bearings are necessary for this design to work and the gears have the same ratio as UMO standard gears, so there is no need to change the default e-steps value.