Our Maker Club started a discussion about how big a 3D printer could be inspired by a custom Printrbot R&D prototype we saw on Google+ https://plus.google.com/+BrookDrummpb/posts/Sytbbd7xxEM . This design allows you use  Slotted Steel Angle Stock with 5/16" bolts to build a 3D printer. These parts give  you a lot of flexibility to build on a large platform - there are real physical limits to the size and shape you can build - its up to you to try out ideas, explore, learn, and have fun. I'm not providing build instructions for this - its not a kit - nor am I claiming this will build a better bot that anything already out there. This is for our Maker club to build, learn and enjoy.  We wanted to share the files online for others to try. Parts are labeled but you will have to decide how you want to build it.  A good resource would be the original printrbot build on youtube. https://youtu.be/6swI8Mer_yw you will have to translate the X Y and Z axis for this bot onto the slotted steel stock on your own :)Sources & Remixes:Printrbot Original by Brook Drumm: https://www.youmagine.com/designs/printrbot-originalAlu Extruder - to - Groove Mount Adapter by TECHGEEK: http://www.thingiverse.com/thing:499483 Printrbot Side Mount Fan by PaulRac: http://www.thingiverse.com/thing:21761