The project is done! The printable area is 247 x 257 x 189mm (XYZ). Z-axis may be any height and depends on the belts and vertical rods lenght. (At this moment I'm using a standard MK2 hotbed). To reduce the cost of construction I changed the motor mount on Z-axis for a standard Nema17 stepper motor (without gearbox) and the counterweight system: http://www.thingiverse.com/thing:798622 But with the geared motor Z-axis also works fine. In this thing where is only Z-axis printable parts. X and Y-axis parts are the same (except extruder mount on block carriage). Download them here: http://www.thingiverse.com/thing:479294 - for lightweight alum profile. http://www.thingiverse.com/thing:637350 - for standard alum profile. Extruder with geared Nema17 stepper: http://www.thingiverse.com/thing:516415 Extruder with Nema17 motor (without gearbox): http://www.thingiverse.com/thing:798580 PS unit cover and fixers: http://www.thingiverse.com/thing:628747 Spool holder: http://www.thingiverse.com/thing:798675 New addon: http://www.thingiverse.com/thing:1014014Aluminum profile: 30x30mm length 400mm (6 pcs) (the "CONSTA" shopfitting profile, lightweight, 1.5mm thickness - look in last fotos, http://www.consta.fi/media/Consta_Systems_PDF_Catalogue.pdf) Belts: GT2 760 - 4pcs (Z-axis may be upwards if use not looped belt) Pulleys: GT2 20 teeth - 8pcs (3 of them may be printed) Stepper motors XY: NEMA17 18mm shaft (my is 0.9 degrees per step http://www.omc-stepperonline.com/9deg-nema-17-bipolar-stepper-motor-09a-36ncm51ozin-17hm150904s-p-267.html) Stepper motor Z: geared NEMA11 (http://www.omc-stepperonline.com/gear-ratio-141-planetary-gearbox-with-nema-11-stepper-motor-11hs200674spg14-p-34.html) I'll upload addon for using NEMA17 motor on Z-axis without gearbox soon (http://www.thingiverse.com/thing:798622). Bearings: 625ZZ - 8pcs Rods: 10x300mm - 2pcs Graphite Lubricating Brass Bearing: 10x14x12mm - 4pcs (like this http://www.aliexpress.com/item/5Pcs-10-14-12mm-JDB-Graphite-Lubricating-Brass-Bearing-Bushing-Sleeve-Oilless/1448887562.html)