Captured Superpulley

This is a small captured pulley used to alleviate friction with small wires or string. I use them in my Jack Skellington articulated hand extender:
http://www.thingiverse.com/thing:1809355
These were designed as tests but worked so well I will use them for future puppet rigging. Use a pliers at the base to free them after printing. A bit of 3-in-1 oil helps them spin smoothly.