This safecracking robot tries every possible combination, one after another:
Combination space optimization is the key. By exploiting of the mechanical tolerances of the lock and certain combination “forbidden zones”, we reduced the number of possible combinations by about an order of magnitude.
Opening the safe took “just a few hours.”
Along the same lines, here’s a Lego robot that cracks combination locks. I wrote about another, non-Lego, brute-force combination lock cracker a few years ago. The original link is broken, but the project is here.
EDITED TO ADD (2/13): In this video, champion safecracker Jeff Sitar opens a similar safe by feel and sound in just 5 minutes and 19 seconds.