screws.
This picture is for the single extruder, but the way to assemble is the
same.
* If the carriage cannot reach to the X axis endstop, you need to add a small block on
the carriage; we have prepared one for you, the No.51A. (Only for orders after 8th,
December, 2015) If you do not have it in your package, you can make one by yourself.
Or you can print one. Download the .stl file here.