My C2 printer developed a "wandering" toothed gear problem. When I compared the extruder of the C2 printer to the R2 printer, the R2 printer has thread lock applied to the toothed gear whereas the C2 printer does not. After carefully measuring the R2 extruder, I determined that the optimal depth should be around 3.3 mm. So I designed a depth gage for this project and printed it with PLA filament on my C2 printer. Materials and Tools: Thread lock compound Allen wrench provided with the C2 printer Printed depth gage ( download the attached STL file ) Printed gage Procedure: Remove the Extruder cover and move toothed gear to the 10 o'clock position. Remove the setscrew (grub screw) and place the gage on the Extruder motor shaft. The gage should fit tight on the shaft so that you won't have to hold it. Put a drop of thread lock compound into the hole and replace the setscrew (grub screw). Tighten the screw to a snug fit. Do not over-tighten! You can strip the threads of the toothed gear. Place a straight piece of filament and confirm that the toothed gear is lined up such that the filament lays in the middle of the toothed area. Also, clean up (wipe with a paper towel) any excess thread lock compound. Wait at least 10 minutes before attempting to do any printing (to give the thread lock compound time to set up ). Finished!