How were the faces carved on Mount Rushmore?

Carving was done by using explosives to blast away the unwanted rock. More than 450,000 tons of Harney Peak granite were removed during the carving of Mt. Rushmore. More than 90% of the rock was removed using dynamite.

Once there was about 3 to 6 inches of rock left to remove, they used a technique called "honeycombing", drilling holes very close together, which weakened the granite so that it was easier to remove.

After the honeycombing, the granite was smoothed with a hand facer or a bumper tool, creating a surface as smooth as sidewalk.