Better washer for Printrbot Alu Extruder v1

I noticed that the black plastic piece (nylon?) that goes through the alu extruder prevented the washer from being flush against the extruder. This added some wobble to the spring arm.

I used some folded up paper to remedy this temporarily, but this piece works much better.

I also noticed that the top portion of my stepper motors threading got stripped, so I switched to a longer M3 screw. I used a 35mm one, but a 25mm should work too (you probably wouldn't need the extra nut in there if yo