QUBD Twoup Gantry replacement

I have heard so much good things about StefanBurger's Gantry replacement, to fix variety problems of original TwoUp designs. (http://www.thingiverse.com/thing:248059).

However, it was very difficult for me to print them with the my original TwoUp printer. After a few dozen of attempts, I decided to design my own.


- Lower height in printing ( somehow, my original TwoUp started causing number of problems after z-axis reaches 1 inch above )
- Shorter print time (so, I can easily repea