... We had one fighter practice where we working on shield wall. I was one the outside of the wall. Using the beard of my battle axe I "hooked and locked" one of the shields (a norman kite) and had such a good bite that I was able to drag the guy all the way out of the wall. Even when the next guy saw what was coming he couldn't stop it happening it to him also.
I love doing that! (As long as my friends can keep the 9' and 12' spears off me.)
Another fun tactic with the axe (or any weapon really) can be had on a bridge/narrow front battle where the number of combatants is relatively small. This will not work in a Pennsic/Lilies type meat grinder.
Setup: You wait patiently at the end of the bridge, slightly off to one side. A brother runs past you onto the bridge with his spear and starts taking pot shots. The opponents see he's "alone" and, invariably, one or two will charge at him.
Result: Your spearman backpedals like mad, right past you and your hungry axe.
The charging opponents are almost always focused solely on the spearman and never realize what hit them. My buddy and I were able to pull this off, repeatedly, at a recent small event. It took our opponents a long time (too long) to figure it out.