I, a 60 Affliction Lock, double-teamed him with a 60 Frost Mage but this method should be effective for many groups.
There's a rock outcropping above one of the huts he patrols (around 48.56). Drop down onto that outcropping and wait for him to path away from the hut. Inside the hut there is a caster. Target him and drop him as fast as possible. If you take too long to kill him the drillmaster may get to within aggro range. After killing the caster check to make sure that the Drillmaster isn't coming back towards you. Jump to the West and run along the mountain side to the wall of the citadel. When the Drillmaster is clear pull the orc against the citadel wall across from the hut.
Now you're ready to take down the Drillmaster! I sent my pet in first and then we both went to town. Be warned, he hits hard (me once for 640 and the mage once for 511) and has a strong knockback. Drop all of the DPS you have on him and he should go down pretty easily.
As a warlock specific option, you could try micromanaging fear and curse of recklessness. I used this method when helping a hunter friend and it worked pretty well. You've got to be careful to avoid the potential adds to the East, though.
There's a rock outcropping above one of the huts he patrols (around 48.56). Drop down onto that outcropping and wait for him to path away from the hut. Inside the hut there is a caster. Target him and drop him as fast as possible. If you take too long to kill him the drillmaster may get to within aggro range. After killing the caster check to make sure that the Drillmaster isn't coming back towards you. Jump to the West and run along the mountain side to the wall of the citadel. When the Drillmaster is clear pull the orc against the citadel wall across from the hut.
Now you're ready to take down the Drillmaster! I sent my pet in first and then we both went to town. Be warned, he hits hard (me once for 640 and the mage once for 511) and has a strong knockback. Drop all of the DPS you have on him and he should go down pretty easily.
As a warlock specific option, you could try micromanaging fear and curse of recklessness. I used this method when helping a hunter friend and it worked pretty well. You've got to be careful to avoid the potential adds to the East, though.