Summary

These are the stl files used to print the modified NYLON 608 bearing as seen in the Instructable
http://www.instructables.com/id/Combination-CNC-Machine-and-3D-Printer/

Instructions

These files are for technical discussions only, as they are modified from the original "Printable 608 Ball Bearing" as released by "TheRooster" http://www.thingiverse.com/thing:4676
The design was modified to accommodate a 0.250â€ center hole rather than the metric hole. It was also modified to accommodate the cooling gradient associated with NYLON.
If you look closely at the photo, youâ€™ll note a few dropped threads at the top of the outer shell. These were outside of the bearing raceway, however an investigation of the top arc should indicate that it exceeds the 45-degree rule.
The seam on the inner raceway is a function of Z axis stepping. A slight touch of a soldering iron smoothed this out.
The bearingâ€™s final usage is for a â€œPre-Programmed Time-lapse Roving Cameraâ€ where bearings are needed for an over-all smooth movement along with a percentage of gear damping that the NYLON provides.
The bearings in the photo are made by perimeter only with no equivalent 45 degree fill. (Just a lot of circles). The end use will require the unit to support 8-10 lbs spread over 4 bearings.
While the final usage RPM is very low, the bearings have been tested at 2,400 RPM for 15+min. With no lubrication, there was a temperature rise of +8 degrees.
Vibration was negligible up to about 2,000 RPM as it became obvious that the inner seam needed more touch-up for higher RPMs.
The parts were not printed on the same run. Inner part first, then Y axis offset and then the outer shell.

NYLON Derivative of the Printable 608 Ball Bearing