I wanted an extruder to use for my experimental hot ends so I took advantage of the long weekend and had a go at Matt Robert's Compact Geared Extruder.
I like the small, modular design, and particularly like how he's approached the transfer of torque in the main gear. This requires three set (grub) screws to go the radius of the gear, and I didn't have any lying around. A few minutes with some M3 bolts and a hacksaw though yielded sufficiently long and stable screws.
Making sure the screws fit
The head of the grub screw should clear the teeth
Completed gear - close up 1
Completed gear - close up 2
Finished Extruder - front
Finished Extruder - back
Finished Extruder - back 2
Finished Extruder - back 3
Hacksaw and M3 Bolts = makeshift grub screws
Correct length to reach the center yet clear the teeth