Came across this on the Reprap Forums.
http://www.youtube.com/watch?v=O3kXFR3aSLs
Looks like they were smart with the H-bot design, using a horizontal carriage. This means any kind of racking forces get pushed against the rod instead of freely twisting with the vertical carriages.
Yeah although looks like he’s having some Gcode problems now. http://forums.reprap.org/read.php?2,238726
Maybe @Stefano_Pavanello can go to his rescue 
Interested to see how he get’s on with the whole feed rate closed loop control thing.
@Tim_Rastall very interesting, I will take certainly a look. We are also evaluating the possibility to tilt the X rods to make them horizontal and reduce racking (that anyway using longer linear bearings it is very very reduced) I’m curious about the Z lifting system with the two rods on the side of the bed.
I’m biased but why not an Ultimaker-style gantry? What are the improvements here?
I wrote in the reprap forum, I think they doesn’t make homing and try directly with G commands, but if you have inverted axis the firmware does not allow the movements outside the printing area. Similar problems that I encounter the first time we try. I like the design of the mechanics, but I do not understand what does feed rate control means, also if you track back with a sensor the quantity of the extrudate, it is the input gcode that generate the correct flow, what can be the benefit of a closed loop?
I have the same design on the BadPrinter2 ( http://baddevices.wordpress.com …I know it can be a lot annoying to post everytime the link, but there are the images that speaks more than words :-)). The improvement is to have only one belt moving around on the same axis, no rotating rods, the motor are fixed so you have a lightweight carriage. I think ultimaker has a very very clever design, but I think it a little bit more complicated respect to the H-Belt (H-Bot)… I think also less moving/rotating parts.
Mine is 2mt for 20x20cm bed
@Luis_E_Rodriguez I think the draw behind the H-bot style gantries is that you get something like the Ultimaker gantry, but with 2 less linear rods needed and no need for rotating rods. Overall it’s a simpler system mechanically, however maybe not so much in the long run when it comes to diagnosing problems caused by racking, etc.
Does anyone know if the LCD holder is published? I was looking for one just like it for my Mendel max 2. It looks great!
curious to watch it working… sounds cool, wondering how many hours you spent building this device…
@Stephen_Jensen Not that I can find. Plenty on Thingiverse, this is the one I intend to use http://www.thingiverse.com/thing:35438