Rokenbok Half Circle Diameter 3

A pair of this part together creates a small circle. Put two together with two of the bearing flange (https://www.shapeways.com/model/1958824/rokenbok-bearing-flange.html) to create a bearing that can spin freely inside a 3 x 3 block opening. These designs are owned by Rokenbok Education (http://www.rokenbok.com) and published under license by kid*spark (http://www.kid-spark.org), a nonprofit corporation, for nonprofit and educational uses. Drawings of these designs are licensed under Creative Commons Attribution-NonCommercial-ShareAlike (BY-NC-SA) 3.0: http://creativecommons.org/licenses/by-nc-sa/3.0/ The drawings may be freely downloaded, modified, and used, providing that attribution is given to Rokenbok Education and the drawings are for non-commercial purposes. Any modified drawings are licensed under the same terms. The drawings are intended for educational and hobby uses only; 3D prints of these designs should not be considered toys or for use by children without adult supervision. The drawings are not guaranteed to print perfectly.