The SolidCore Z-Axis Bracket Mount:
The SolidCore Printer has two different z-axis designs. This z-axis bracket design mounts the z-axis lead screw stepper motors on the bottom of the frame. The bracket has a 20.1mm counterbore to seat a 20mm brass lead screw nut.
see lead screw nut
Independent Driven Z-Axis Motors / Single Z-Axis Motor
Both z axis designs use 3-point bed leveling.
For more information see:
SolidCore 3D Printer
Download 3D Model
Thingiverse Z-Axis Bracket
Thingiverse SolidCore Printer