Abstract: A blind fastener with a pin having a pin shank which extends through a cylindrical main sleeve and expansion sleeve whereby it can be gripped and pulled by an installation tool with the pin having an enlarged pin head at the blind end of the pin shank. The expansion sleeve is located between the pin head and the inner end of the main sleeve and is adapted to move into the inner or blind end of the main sleeve to form a first tulip shaped blind head for clamping workpieces together in response to a relative axial force applied between the sleeves and pin by engagement of the pin head with the expansion sleeve. As the axial force is increased the pin head is moved into the expansion sleeve to form a second tulip head to further clamp the workpieces and to secure the pin, main sleeve and expansion sleeve together at that end and is moved closely adjacent the workpiece surface at the blind side to form a high strength blind head.