The first stone axes had a groove all around the stone. The handle wrapped completely around the groove. Later, people in the eastern United States changed the style to a partial groove on the top and sides, but full grooved axes continued to be used in much of the Southwestern United States.
This was a great chopping tool for cutting down trees. This axe design was a technological advancement around 2000 years ago. Here’s why – the celt head is tapered so with every chop of the axe, the head wedges tighter into the handle.