Abstract: A series of adjoining cam discs are mounted on a foot having an inclined surface, with the cams surrounding a stem connecting the foot and a head of a diameter to fit within a borehole in rock. The stem extends axially between the head and the foot, while the inclined surface is spaced from the head and is inclined with respect to the axis of the anchor. The head has threads for receiving corresponding threads on a bolt which extends through the foot and stem, while the flat cam discs have a width less than, and a length greater than, the diameter of the borehole. The anchor is moved into the borehole and the cam discs are caused to engage the wall of the borehole, the bolt then being turned to thread the head against the cam discs and force the ends of the cam discs against or into the wall.