Do bigger brains lead to smarter tool use?

In evolution of man: In the evolution of man, bigger brains led to greater intelligence and thus smarter tool use. However in humans, it is not the overall size of the brain that determines intelligence, but the size (complexity) of the cortical ribbon that ultimately determines intelligence. This work was performed in infants, and though the study suffers from design flaws, but the thesis is probably correct.

Brain : Not necessarily - several prominent people who were incredibly bright, such as einstein whom actually had small brains.