Abstract: The method and means for installing blind fasteners involves a pulling head design such that will cause the stem of the rivet pin to be broken at a predetermined location by a trimming or notching action of the head. This allows a previously unweakened blind fastener pin to be weakened for breaking at a prescribed location after the fastener is installed, thus accomplishing a pin break off substantially flush with the head of the fastener over an extremely wide range of thickness and types of materials being fastened. The pulling means may include a support housing which slidably receives a chuck assembly for pulling the blind rivet pin. A collet is also mounted in the support housing. The collet has suitable cutting edges for weakening the pin stem immediately adjacent the head of the rivet sleeve when appropriate load forces are reached. Cooperating cam surfaces on the support housing and collet react to the load forces to effect this weakening action.