Abstract: A headed steel pin for a multi-grip fastener of the pin and swageable collar type has a homogeneous microstructure, and consists substantially entirely of sorbitic tempered martensite. Suitable coarse-grained medium carbon steel is shaped to form a headed pin having a plurality of identical, regularly spaced, annular, combination grooves each able to function alternatively as a locking groove, a pulling groove, or a breaker groove. The shaped pin is heat treated, the steel rendered homogeneously martensitic and then tempered at a temperature approaching as closely as practicable to the lower critical temperature of the steel, to convert the martensitic steel entirely to sorbite. The finished pin has a suitable balance of brittleness, toughness, ductility and impact strength, and tends to break cleanly and reliably at a selected one of the combination grooves when the fastener is installed in a workpiece.

Abstract: A threaded fastener for installation in threaded engagement with an initially unthreaded apertured workpiece and which after installation can be removed in the manner of a screw or bolt, has a shank and an enlarged head. At least part of the shank intermediate between its ends has an external screw thread having a sharp crest, and can be radially expanded to cause the thread to embed in the workpiece. A bore extends through the head and the entire shank or at least the threaded port of the shank for receiving means for expanding the shank. An end portion of the shank remote from the head may be unthreaded to avoid splitting of the shank during expansion.The method of installing the fastener involves pulling a tapered mandrel along the bore to expand the shank. The mandrel may have a key-forming head of non-circular cross-section whereby the bore of the fastener can be adopted to receive a key of non-circular cross-section for turning the fastener in the workpiece.

Abstract: A threaded fastener for installation in threaded engagement with an initially unthreaded apertured workpiece and which after installation can be removed in the manner of a screw or bolt, has a shank and an enlarged head. At least part of the shank intermediate between its ends has an external screw thread having a sharp crest, and can be radially expanded to cause the thread to embed in the workpiece. A bore extends through the head and the entire shank or at least the threaded part of the shank for receiving means for expanding the shank. An end portion of the shank remote from the head may be unthreaded to avoid splitting of the shank during expansion.The method of installing the fastener involves pulling a tapered mandrel along the bore to expand the shank. The mandrel may have a key-forming head of non-circular cross-section whereby the bore of the fastener can be adopted to receive a key of non-circular cross-section for turning the fastener in the workpiece.