inspired by: https://www.youmagine.com/designs/um2-feeder-on-um1for use with: https://www.youmagine.com/designs/alternative-um2-feeder-version-two---UPDATE (v4.0):for this version, which is even more silent than version 2.0, you only need 4 fan dampeners like those: http://www.amazon.com/GELID-Solutions-Silicone-Vibration-Dampening/dp/B003Q5GI2U---UPDATE (v2.0):i updated the design and uploaded a new model with dampers (you need three dampers 15x15mm  - M4 and three screws PH2 M4x10mm), works pretty good so far ;). i also added a picture that compares the noise before the dampers where installed and afterwards, it doesn't look much but it is and it also is way more silent than the original feeder.i recommend a 1.2mm walls and infill around 25%, no support is needed since it is integrated at the model files (only true for damped version)---Since the original version didn't fit for me, i redesgined the um2 feeder adapter for the um original.This one was a perfect fit at mine - it's also super rigid as you can see at the following video (printed with 0.8 shell, 30% infill, "support everywhere"!!!):http://youtu.be/1DHHGL55-m4https://www.youtube.com/watch?v=TK3vZnc9REc---I reach up to ~12mm³/s without any underextrusion (see picture above).https://www.youtube.com/watch?v=bEfR5EOvXLYupdate: since I now calibrated my feeder I reach now up to 18mm³/s , didn't tried more so far...https://youtu.be/8yH8ZTfmxHoThe E-steps per mm for an Mk8 drigear should be around 365 as I read, since I am still waiting for my 400steps/rev. motor I cannot confirm that. At the original stepper it is much lower (but the original motor does not work for high quality prints - 1.8° steps are just too unprecise!).update: the stepper arrived and 340 works very fine for me! (see here for more information: http://reprap.org/wiki/Triffid_Hunter%27s_Calibration_Guide/de)update2: i was still extruding way too much! 302 is perfect now, to calibrate for the first time do the following:- pop the bowden tube out the hotend- preheat PLA (to activate the extruder motor)- extrude a bit until you can mark the filament at the bowden end- let it extrude 10mm- mark again and measure as accurate as you can- new E-steps = old E-steps * (10/measured mm)I also recommend some rubber washers between motor and the adapter to further minimize noise (it is very quiet compared to the original!). you can also use a selfmade silicone-damper as me: https://www.youmagine.com/designs/nema-17-silicon-damper-stencilAs an UMO-user you will not have an clamp for the feeder, I suggest that one:http://www.thingiverse.com/thing:46318