K8200/3Drag Z axis bearing support (rework of http://www.thingiverse.com/thing:175137)

I reworked the geometry to eliminate non manifold faces, to clean up the geometry and to align the centre of rotation better to the original kit piece. I have also recessed the screw in order to be able reuse screw and washer from the Velleman kit, but I don't know if the 3Drag uses the same hardware. The distance of the shaft from the frame matches http://www.thingiverse.com/thing:232446
(and my own rework http://www.thingiverse.com/thing:443084).
The second picture shows the same object wi