I made this from scratch using pictures as reference. I borrowed the worm gear model from Johann517's Spider Rover and modified it slightly. You can view the original design at:

http://www.thingiverse.com/thing:468872

This is the famous killer metallic sphere from the 1979 cult movie classic "Phantasm". If you haven't seen this horror film, then you must be living underneath a rock. You will need to print out two blades. The sphere has pre-made slots you can stick the blades into. You might need to file or trim the slots to make a good fit. I was thinking about casting a life size aluminum version and polishing it to a mirror shine. You could also use chrome spray paint and some clear coat. I would recommend using support material just to be on the safe side. EDIT 05-16-2016: I cut the bottom half with the drill into two pieces for easier printing. Just glue the two bottom pieces named bottom_a and bottom_b to make up the bottom portion of the sphere. I used Zatoichi's make where he split the bottom drill part into two pieces as inspiration. Thank you.

Please do not use this model for commercial purposes.