The various embodiments disclosed and pictured illustrate a hammer for comminuting various materials. The embodiments pictured and described herein are primarily for use with a rotatable hammermill assembly. The hammer includes a connector end having a rod hole therein, a contact end for delivery of energy to the material to be comminuted, and a neck affixing the connector end to the contact end. The neck is formed with at least one neck recess therein. In other embodiments, one or more shoulders are positioned around the periphery of the rod hole for added strength. In still other embodiments, the contact end is configured with more than one contact surface.