"It's to cool down the drill bit," Autor explains, holding up the bucket. "When drilling through rock, the drill gets overheated and might break if it gets too hot. At least, that's what I've read anyway; I've never done it myself."

He crosses to the right wall. "Over here, if you don't mind," he says, adjusting the safety glasses perched awkwardly over his own. "We can install both pulleys and thread the rope through them. It should be easy enough."