A self-drilling anchor for use in a friable material comprises a body having an axis, a flanged rear end, a drilling front end and a generally cylindrical portion therebetween having an outer surface with a thread disposed thereon, wherein the body forks, beginning at a predetermined distance from the flanged rear end, into a first leg and a second leg, the first leg extending forwardly into a drilling tip and having a generally rearward facing shoulder angled obtusely outwardly with respect to the axis, wherein the body has an axial bore for receiving an elongate fastener, the axial bore extending substantially through the flanged end and the generally cylindrical portion and leading to the generally rearward facing shoulder, wherein the anchor has a drilling mode wherein the second leg nests behind the generally rearward facing shoulder of the first leg, and an anchoring mode wherein the legs are pivoted apart from one another.
A sprue dowel has a radially projecting embeddable portion (12) and an attachment portion (21) formed as a hollow cylindrical shaft (24) provided with a plurality of spaced from each other, furrowed retaining projections (26, 27) formed on an outer circumference of the shaft and extending parallel to a longitudinal axis (25) of the sprue dowel (11).
