Originally shared by Paweł Dobrowolski
Well, I think that it might work…
http://www.youtube.com/watch?edit=vd&v=36YvqCtrS3s
Why did you grab the filament 20+ seconds in? No hot-end yet? so still waiting for performance under pressure… 
I tried to stop extruder. I had to check how perform stepper motor(and gears) under pressure.
looks promising. good job
@Alex_Wiebe Holding the filament back is the accepted method of checking the extruder’s pulling strength. You should not be able to stop the filament by this method. If you can then something is wrong.
For curious fellows, teeth on allen bolt is pointed in wrong way 