Abstract: A flush break blind fastener is provided having as principle components a stem member, a drive-nut, and a deformable annular means. The stem member has an externally-threaded-portion on the accessible-side thereof, and may have a stem-head on the nonaccessible side thereof. The drive-nut is screwed onto the externally-threaded-portion of the stem member. The deformable annular means has as principle parts a head which is larger in diameter than the diameter of the boreholes of the workpieces, and an intermediate-part adjacent the head, and a deformable tail-part adjacent the intermediate-part and abutting the stem-head for securing the workpieces when the fastener is set. The outer-portion of the stem member contains a turning means for rotating the stem member relative to the drive-nut.