Summary

This is drawn fairly large (3"). Scale it to your needs.
Just because I wanted something to draw.
Lost PLA casting?
http://en.wikipedia.org/wiki/Knucklebones

Instructions

there are several ways to print this. I would suggest up, with supports and a raft, but it could be tipped on it's side for no supports, not much of a savings with definite less quality. Definitely needs mass in the spherical ends, so crank up the shells.

Print 2 of the half versions for FDM type printers. Add a brim to keep peeling issues at bay.

Spin Jack Toy