When I bought my Printrbot Plus, it came with the flattened X and Y axis motor shafts, but the 10 tooth pulley had a full round shaft hole, with a very small set screw to hold this pulley in place. This worked great for a while, but unfortunately, the set screw inside the pulley was only 3mm and held in place with just the plastic of the pulley. Inevitably, this worked it's way loose and the Y axis motor pulley would migrate up and scrape against the bottom of the print bed. While scraping against the bottom of the print bed, this would produce faulty prints that were just unusable.

This is a mod of the original Printrbot files posted by Brook Drumm: thingiverse.com/thing:16990

The details of this mod are as follows:

1) Adds a place for the 3mm nut that came with your Printrbot parts, please click "Thingview" in the above pic to see the underside of this pulley.
2) Shortens the overall length of the pulley for a more customized fit to your printer.
3) Both the original set screw, from your original pulley, and the short 3mm allen head screws, included with your Printrbot, will work with this mod.
4) Designed for the flattened motor shafts, not the old round shafts. This will not work with the old round motor shafts.
5) All files associated are configured for ABS plastic.
6) The Gcode file was created using Slic3r 0.9.7, and is centered on X: 75 Y: 75 for either the 6 inch or 8 inch Printrbot models. Regardless of the Printrbot model you have, just download the Gcode and go.
7) The Gcode above will print 2 pulleys. It's best to do this in case one pulley doesn't come out, maybe the other one will.

CAUTION: THIS IS AN ADVANCED PRINT.

While the Gcode above is optimized for all Printrbot models, this is a highly detailed print that will take 2 hours to complete. If your Printrbot is not fully calibrated, on all axes, than this will not be a usable part. Please be sure you have a few 3D prints under your belt before attempting this one. Have a look at some of my other projects for a little printing practice.

The STL file above has been cleaned and optimized using Netfabb.

If you haven't done so already, please print my "Printrbot Y-Axis Mod" so you can level your print bed and give your current 10T pulley some clearance under the print bed.

thingiverse.com/thing:48299

Thank you,
Tom Heibel
Sticky Pod