Instructionsonce printed take your old feeder apart and use a standard nut (not one with a lock thread) plop the bearing on and away you should go. ITs a little tight getting it in there but it works nice. BTW make sure you print it with 100% fill.. anything less will crumble under the pressure that is needed to push the bearing against the filament. One note I added little black dots to the out side of the bearing with a sharpie about 15-20 of them . Reason is so through the gap I could look in and check to see if the bearing was moving. (flash light needed for this) Great way to see if your actually getting movement on the print or not.
Technical
here is where you can get the Bearing
http://www.drillspot.com/products/462029/Dynaroll_SMR128ZZ_A5_Miniature_Ball_Bearing
http://www.bearingboys.co.uk/MF128-ZZ_Flanged_Shielded_Miniature_Ball_Bearing-62818-p
(hopefully I found the right one at Bearing Boys if not please inform me and Ill fix the link.. Everything is the same except the manufacture and the first 3-2 letters. From SMR to MF )
If anyone has printed this I would love to hear how it worked out for you.
Mine is still working as well as the day I made it. Might have to print another one due
to compression where the screw pushes against where the bearing is since there is no Metal in there to keep it from denting in the plastic..