Install the new 12mm diameter linear rails to the right size (stepper motor side) of the X-axis gantry. Install these loosely as you’ll need to later align them once the X/Z carriage is installed. Note: New M5 x 20 screws and washers have been provided with your upgrade kit. Use the new M5 hardware with 1 M5 washer placed under each X-axis rail screw head.