I finally decided to try Greg's extruder (from the felt branch of PrusaMendel). The gears meshed and turned but there was a tiny bit of space in between them giving the extruder a bit of unwanted wiggle room. I had some leftover felt so I threw that on there and it works great! It also has the side-effect of completely eliminating any clicking noises.EDIT: After only minor use, the felt slipped off. This needs a little more thought. Perhaps a couple more tabs would provide the necessary stability.EDIT: I don't recommend anyone use this. It worked for a while, but the felt got stretched/compressed and it stopped working. Perhaps another material may work better?Cut out with scissors or laser cutter (? I don't know if laser cutters work with felt or not), wrap around the small gear on the extruder and glue the tabs to the side of the gear.Hint: if you don't want to take the time to download the files, it's just a strip of felt with tabs on the end. I doubled the circumference of the small gear.