Abstract: A mandrel has an anti-dropping-off portion that is formed between a head and a breakable portion thereof. In the anti-dropping-off portion, a plurality of latching ridges is formed which have peaks that protrude outwardly in the radial direction and frictionally engage with the inner wall surface of a sleeve. The latching ridges are formed in the outer surface of the portion of the mandrel that is between the head and breakable portion thereof, so as to be diagonal relative to the circumferential direction of the outer surface of the mandrel and to cross each other, with the peaks thereof formed in a twill pattern protruding out from the outer surface of that mandrel portion.

Abstract: A blind rivet comprising a rivet body with a hollow shank and a flange at one end has a mandrel extending through the shank of the rivet body and having a head with cutting edges that facilitate expansion of the end of the rivet body shank opposite to the flange when a pulling force is applied to the mandrel to break the mandrel and extract a portion of the mandrel from the rivet body shank. Cooperable portions of the rivet body shank and the mandrel engage one another and prevent rotation of the mandrel with respect to the rivet body. Other cooperable portions engage one another to ensure that the mandrel breaks without undue movement of the head into the rivet body shank.