A drill head borer is configured to be attached to a rotary auger including a helical blade. The borer includes at least one wing extending radially away from a body centered about a longitudinal axis. An aligning ledge is formed in the drill head borer configured to self-align the drill head borer with the helical blade without the need for substantial measurement by a user. The borer further includes a plurality of teeth arranged in a convex configuration, along the wing when viewed from above. When viewed from the side, the teeth are angled at a lifting pitch angle.