SKYWALKER, METAL - MEDIUM SIZE CLANK

This's a Skywalker Sound sound effect.

Movies

 * 9 (2009)
 * Pirates of the Caribbean: At World's End (2007)

TV Series

 * Star Wars: The Clone Wars (Used mainly for the "footsteps" of Vulture Droids)

Audio Samples
The Clone Wars 2008 Series is the best source, used for Vulture Droids walking (i.e. "Mystery of a Thousand Moons")