A tool for crimping work pieces to one another is disclosed. The tool is mounted on a power actuator having a reciprocating ram for effecting crimping. The tool includes a body engageable with the workpiece. A movable head is mounted on the body and receives the ram. A jaw is pivotably mounted on the body. A link connects the head to the jaw, which pivots in response to the ram engaging and moving the head. The jaw has a tooth that penetrates the work pieces upon pivoting of the jaw. Penetration of the work pieces by the tooth crimps the pieces to one another. A receiver is mounted on the body to permit its engagement with the actuator by means of an attachment device adapted to a particular actuator. The tool may be removably attachable to the actuator or permanently attached thereto.