Based on the EZStruder Knob by h3ss I added a notch to his design which mates with the notched portion of the stepper, allowing for better contact and more force to be exerted on the filament during hand extrusion. I also closed off the back as a purely stylistic choice. Print with either ABS or PLA. No support needed. I used: Prototype Supply ABS 0.2mm Layer Height 2 External Perimeters 25% Infill Simplify 3D Time: 30minutes