The frame is thinking for you don't have to threading it.The structure has two bars to stiffen the joint between the frame and the axis Y.Easily leveling platform with three supporting points and only two screws to level.Tensioning belts on the X axis and Y. The X axis is directly interchangeable with any Prusa I3 printer and it's a great advantage.Front and rear aluminum parts to replace the threaded rods and improve aesthetics.This 3d printer has a long way in Spain, it was designed almost two years ago, I would like that it wil be knonw arround the world.You can see more documentation and the last modifications at the github:https://github.com/Mecan0/Code/Other interestings links:Assembly instructions in Spanish:https://drive.google.com/file/d/0Bz2-pRbzwDNWWjBjckh4Nkh5Yzg/edit?usp=sharinghttp://lab.shuttl3d.com/imprescindibles/montaje-power-codeThe openscad files are thanks to J Rodrigo.Leveling videos:https://www.youtube.com/watch?v=3MagXojsxTohttps://www.youtube.com/watch?v=LGQ_Vna2ZAwA video: https://www.dropbox.com/s/e3o5o18xe726tea/2014-09-27%2009.07.35.3gp?dl=0