The axe was often the choice of the poorest man in the Viking age. Axe heads were made of iron and were single edged. A wide variety of axe head shapes were used in battle, a wedge-shaped cross section was most typical. The cross section of the head near the edge was sometimes diamond shaped, which provided greater strength for a given weight of iron.
The head of the axe that is fitted has to resist both pulling and pushing forces. A number of ways to affix the head were used to prevent it from flying off the shaft. Some axe hafts might have been wrapped to prevent breakage.
The haft was made of wood and it's length was sized for the intended use as it had to balance the axe head. Axes with smaller heads had shorter hafts and were used one handedly. A short haft of about 70 cm seems to be common. The longer haft was about 140 cm in length and was used with both hands. The axe head was bigger and the warrior had a longer reach with this.
Axes were often light, fast, and well balanced. They were good for speedy, deadly attacks, as well as for a variety of clever maneuvers.
Axes with shorter hafts could easily hidden behind a shield or under a cloak.
The shape of the axe head allows it to be used for a variety of maneuvers. For example it can be used to hook an opponent's neck, ankle or other body part throwing him off balance. Another great move would be to place the axe head behind the edge of the shield so the enemy could be disarmed by pulling the shield away.
The pointed 'horns' of the axe's head were kept sharp so they could be used to pierce a weak body part. The backside of the axe head was sometimes used to knock out an opponent so they could be captured.
Source: Hurstwic: Viking Axe
The attributes of the axe are decent. It has a damage throw of 1D+3 which has a range of 3 to 7 hit points. There is a small disadvantage on the defense of -1. The weapon is used with one hand and the distance class is melee (M). The chance the haft will break is 20% using a D20 die.