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
Ratio 15:1(Marlin_config 1881steps per unit mm)
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