Abstract: A flat strip of metal formed as an expandible wedge having an inside triangular space bounded by jaws that correspond to the beveled sides of the wedge and a rear portion that corresponds to the thick end of the wedge opposite from its apex. The apex ends of the jaws are sharpened. A shaft extends through a hole in the rear portion of the wedge and has an eccentric inside of the triangular space. The shaft has a projection that is larger than the hole and can be reciprocated for the projection to drive the wedge and can be turned for the eccentric to spread the jaws.