Z-axis lead screw mount

This is a Cobblebot lead screw z-axis re-design. It brings the lead screws closer to the gantry cage, removing the flex from the mount plates. I suggest running 3 lead screws with the z motors in series with a 24v power supply, but this design can be applied to 2 lead screws as well. It allows for custom gear reduction via a timing belt loop to drive the lead screw from a NEMA 17 stepper motor.