THere are a few threads on site about greenteeth, and bearing on the small Rayco grinders, use the search and you will find some info. As for the small green teeth, they work very well and are lighter than the standard size. Problem is the nuts that hold them are so small they wear down quickly and I had use a vise grip to get them off. Had to replace the nuts every time I rotated the tooth. I am not a big fan of the greenteeth and after trying a few different types went back to Rayco teeth and just retip them when they get dull. Cuts the cost in half and keeps the machine and me happy.