tangs 44 are protected from contact with the installation media 100 and 104 by the bowtie tip 24 and possess radii and chamfers sufficient to prevent snagging with installation media 100 and 104 during removal of the rivet 20 the tangs 44 temporarily axially deflect when the washer 50 is moved to the locked or unlocked position returning thereafter to a rest position the tangs are sufficient in size and span to cause interference with the washer 50 and require an adequate amount of torque allowing for hand installation while resisting vibration or loosening action by way of example a rivet device 10 having a shank diameter of 0 180 u2033 and an overall height of 0 545 u2033 may have a tang height of 0 020 u2033 as stated above the washer 50 provides a pair of detents with the rivet tangs 44 by way of two pair of obstructions 56 located on the inner diameter 58 of the washer 50 the bottom 54 of the washer 50 is placed over the bowtie tip 24 of the rivet 20 the washer head 62 is recessed at a depth and diameter sufficient to permit counter rotation between the washer 50 and the bowtie tip 24 relative bidirectional rotation of the rivet 20 with respect to the washer 50 or of the washer 50 with respect to the rivet 20 engages the rivet tangs 44 with the washer obstructions.