Fastening collars, multi-piece fasteners, and methods for fastening

A method for fastening, the method comprising:

• providing a multi-piece fastener comprising
• a fastening collar comprising
• a first collar end,
• a second collar end, and
• an elongate portion intermediate the first collar end and the second collar end and defining a longitudinal axis of the fastening collar, wherein the elongate portion comprises
• an external collar surface,
• an inner collar surface defining a collar cavity, and
• a groove on at least one of the external collar surface and the inner collar surface, wherein the groove extends a first distance along the longitudinal axis, and
• a pin configured to be at least partially received in the collar cavity of the fastening collar, the pin comprises a shank comprising
• a generally smooth region, and
• a second region comprising at least one of an annular shoulder, a groove, and a threaded region;
• inserting the first pin end of the pin into a bore of a structure and the collar cavity, wherein the groove is positioned over the generally smooth region;
• and
• forcibly contacting the elongate portion of the fastening collar with a contact surface of an installation tool, thereby forcibly contacting the structure with the second collar end of the fastening collar and deforming the elongate portion onto the shank of the pin, including deforming the groove.