While developing a Moineau Extruder and an Oogoo Mixer/Extruder, I realized I needed a way to feed viscous, gooey material to the extruders. Using a medical-type syringe wasn't a good option since the outlet was too small for really viscous materials (like peanut butter). This design is the result. You can read more about it here: https://hackaday.io/project/3794-syringe-pump Video of it pumping peanut butter: http://youtu.be/0kxmUv-6fbM I will add instructions and the FreeCAD source files soon.