Summary RepRap, extruder with NEMA14 stepmotor. It's light and cheap to build. My actual step motor is 25mm deep (very small), and just print one job at 150m/s (Marlin_config 1881steps per unit mm) You need: 3 bearings 16x8x5 (Block/ filament gripper) 2 bearings 8x3x4 (middle gear) heat sink, if using very small motor, (mine start skipping at 65 C) and some nuts/bolts https://youtu.be/BVO7R3UbIoM Gear configuration copy from: Paste Extruder - 10 cc V2.1 - Extrudeuse a pâte by Shapescribe, published Dec 14, 2014 http://www.thingiverse.com/thing:591849