I finished the bowden tube extruder for my Rostock Mini build. It uses airtrippers V3 Bowden extruder for the coldend, a makergear hot end, and the rostock-mini hot-end holder.
I can actually print things with the rostock-mini, and say that I built a 3D printer using my (other) 3D printer. However, I have a lot of work to finish up before the printer is done (or even prints well). Now that I have all of the parts working together, I need to finalize the mounting position of everything, then I can laser cut the final 1/4″ acrylic top and bottom plate with all the appropriate mounting holes. I think I will be putting the airtripper extruder on the top plate, as opposed to under the body of the printer. I may also rig up a spool roller on the top as well. The 1/4″ acrylic (vs the current 1/8″ birch plywood) will give the printer a lot of needed rigidity. I also have to play with using the set screws on each carriage to adjust the height of the extruder head over the entire print surface, and determine exactly how I want to mount the glass build plate and bed heater.