http://en.wikipedia.org/wiki/Macuahuitl

EDIT: image seize (alf)
Edit:
"...According to one source, the macuahuitl was 3 to 4 feet (0.91 to 1.2 m) long, and three inches (80 mm) broad, with a groove along either edge, into which sharp-edged pieces of flint or obsidian were inserted, and firmly fixed with some adhesive compound. The rows of obsidian blades were sometimes discontinuous, leaving gaps along the side, while at other times the rows were set close together and formed a single edge.
The macuahuitl was made with either one-handed or two-handed grips, as well as in rectangular, ovoid, or pointed forms. The two-handed macuahuitl has been described “as tall as a man”..."
And another one:
http://en.wikipedia.org/wiki/Tepoztopilli

"...The tepoztopilli was a common front-line weapon of the Aztec military. The tepoztopilli was a pole-arm, and to judge from depictions in various Aztec codices it was roughly the height of a man, with a broad wooden head about twice the length of the users' palm or shorter, edged with razor-sharp obsidian blades which were deeply set in grooves carved into the head, and cemented in place with bitumen or plant resin as an adhesive..."