In short. You need an UMO+ Kit, a heated bed upgrade kit, our redesigned laser files and order some new parts (ex. longer axis). We enclosed a BOM list with all the parts needed to build this fabulous machine. If you have ever build an Ultimaker Original yourself, then this is a piece of cake ;-) Well.... Below some things to we find out. We used the Ultimaker Original +. This is the new Ultimaker Original with the same motherboard as the Ultimaker2 and heatedbed. The printer we also use in our 3Dkanjers projects. It's an open source 3D printer so all the files available on GitHub (https://github.com/Ultimaker/Ultimaker-Original-Plus). Laserfiles The original laser files of all wooden components can also be found on GitHub. Our goal was to make a printer twice as wide and that affects nearly all six sides of the 3D printer. We redesigned almost all the files with Adobe Illustrator. During this phase we soon discover that a bigger 3D printer allows us to make some improvements. Such as moving the X-motor to the left in the vicinity of the Y-motor and moved the feeder more to the center. We enclosed all the new Laser files (.eps and .pdf). We didn't changed the 4mm laser files. New parts You can use almost all the original parts from the Ultimaker Original + kit. An exception are the X-axis and timing belts for the X-axis. Timing belts can be ordered online and longer shafts (hardened ground) are custom ordered from Technical Trading Netherlands (thn.nl). The Ultimaker Original + has a heated printbed. We want to maintain our version and therefore started looking for a larger version. Not available (to our taste). That is why we have chosen to connect two heatedbeds. We also replace some parts with self-printed parts. Sometimes because it can and sometimes because they are simply better. We replaced the slider blocks with the Twister Blocks from Hrvoje Cop (https://www.youmagine.com/designs/twisterblocks - some adjusted made on left block) and instead of the wooden inside caps we made our own "rod spacers", inspired by the Ultimaker 2. And of course, two Ultimaker Handles made by Silvius (https://www.youmagine.com/designs/ultimaker-handle). We connected the long timing belts on the X-axis with the Timing Belt Coupler of Yergacheffe (http://www.thingiverse.com/thing:29640). Simple, but effective. Assembly The assembly went pretty smooth. No major design errors. The idea to connect two heated beds next to each other on a wooden plate, however, was not a success. It was almost impossible to get the bed leveled. The wooden plate is replaced by two aluminum tubes (1.5 mm x 1.5 mm), and then fixed to the "Print Table Base Plate" with the 3 curling nuts. Connecting two Heated Beds You can connect 5 stepper motors (X, Y, Z, extrusion 1 and 2), two heaters (head 1 and 2) and one heated bed on the Ultimainboard 2.1.1. The first thing we have tried is to connect the second bed on heater 2. But once the two were heating, the security of the adapter did his work. No success. Then maybe a circuit in series? That works, but both heated beds will not go higher than 50 degrees. Also no success. The power adapter has an output of 24 volts 9.2 amps (221 watts). Not sufficient for two heated beds (and a printhead). Since we still had some parts lying of a Heated Bed Upgrade Kit (for the Ultimaker Original), we opted to connect the supplied Heater Board V1.1 on heater 2. Now we have two power supplies, but it works. We enclosed a file that describes how we connected the Electronics to the heater board (pdf). Also enclosed: New heated bed PCB cover (.slt) and Cable Clamp. Software The Ultimaker Original + comes with one printhead and a heated bed. The standard Marlin Firmware (UM2.1: https://github.com/Ultimaker/UM2.1-Firmware) should be adapted for 2 print heads (print head 2 -> heated bed 1). In addition, the 3D printer is twice the size of the 3D printer defined in the software, so there was work to be done. The first thing we have tried is to build online a new firmware via Bultimaker website (https://bultimaker.bulles.eu). This made it possible to get the second bed working, but not to change the size of the printer. We thought to find a detour by imparting an additional G code: M208, but unfortunately this only works on RepRapFirmware. So we installed Arduino and found a good Marlin version. We used the version of Bultimaker. We found the variables concerned pretty quickly in Configuration.h . We also employed a language exchange (Dutch) and add the missing translations. After compiling we got a working hex file out of it with some extras. We enclosed the .hex file (firmware, Dutch and English). Cura and Gcode You also have to change some settings in Cura and put new Gcodes in your files (and delete some). Details can be found in document: Cura settings and Gcode. We made also an Gcode to perform Bed Leveling.