Blind fasteners and methods of fastening

A blind fastener comprising:

• a sleeve comprising
• a head portion, wherein the head portion comprises at least one feature configured to receive a torque selected from the group consisting of a substantially flat side, a rib, a spline, an indent, a knurl, a lobe, a bore, and a tab,
• a first sleeve end,
• a second sleeve end,
• an elongate portion extending intermediate the first sleeve end and the second sleeve end, and
• a cavity extending from the first sleeve end to the second sleeve end;
• and
• a mandrel at least partially disposed through the cavity of the sleeve, the mandrel comprising
• a first mandrel end disposed adjacent to the first sleeve end and comprising an enlarged portion having a diameter greater than a diameter of the cavity, wherein the enlarged portion is hollow;
• wherein the elongate portion is configured to at least partially deform into threads of the threaded bore thereby forming external threads on the elongate portion and the diameter of the enlarged portion is configured to be at least partially reduced responsive to forcible contact between the enlarged portion and the sleeve,
• wherein the blind fastener is capable of removal from the threads in the threaded bore after forming the external threads by rotation of the blind fastener.

A method for fastening, the method comprising:

• inserting a blind fastener into a threaded bore in a structure, the blind fastener comprising:
• a sleeve adapted for installation into the threaded bore, the sleeve comprising
• a head portion,
• a first sleeve end,
• a second sleeve end,
• an elongate portion extending intermediate the first sleeve end and the second sleeve end, and
• a cavity extending from the first sleeve end to the second sleeve end;
• and
• a mandrel configured to be at least partially disposed through the cavity of the sleeve, the mandrel comprising
• a first mandrel end disposed adjacent to the first sleeve end and comprising an enlarged portion having a diameter greater than a diameter of the cavity, wherein the enlarged portion is hollow;
• and
• deforming the elongate portion onto threads of the threaded bore and reducing the diameter of the enlarged portion, thereby securing at least a portion of the blind fastener into the structure.