Thingiverse is a great place to share stuff. I did not invent this or make the original stl file. I saw it here on Thingiverse, and grabbed it up. I know a cool design when i see one. I did, however, modify it to my needs. I made the bottom stem a little bigger and added support for printing. Then made it a through hole for a long shaft. I added the blender file so you can change the size of the shaft. Though shaft or any size or length. original stl file came from here http://www.thingiverse.com/thing:956458 http://www.rexresearch.com/harmanprop/harmanprop.htm the inventor of this thing is awesome http://www.google.com/patents/US7862302 MORE LATER! after it prints