Knappy time! Knappers use Stone Age techniques to carve tools

Seated on a low bench, Jim Spears used a piece of deer horn to whittle down a heavy chunk of Missouri flint. For an hour, he tapped, whacked and smoothed the hard rock until it was transformed into a delicate and potentially deadly artifact: a replica of an Indian arrowhead known as a Dalton point.

"Every stone is different and every stone is a challenge," said Mr. Spears, as he chiseled away and the arrowhead grew thinner and sharper. "It helps me get into the minds of ancient people."

At 62 years old, Mr. Spears is one of the country's finest flint knappers, a breed of die-hards who re-create ancient arrowheads, knives and tools using original Stone Age techniques.