Abstract: A compressibly resilient strip is retainably disposed in an axial slot in a threaded shank which is advanced through a bore in a plurality of workpieces. A rigid retainer member is inserted into the slot to urge the resilient strip against the bore to increase the resistance force between bolt and bore against separation until such time as the retainer member is removed.In another application of the invention, a threaded fastener having a head and a shank is inserted into a through opening in workpieces until the end protrudes and is fastened with a nut. An axial slot in the threaded fastener is aligned with an axial channel of the nut. A strip, having a protruding lug near its distal end, is passed through the slot of the threaded fastener until the protruding lug enters the channel of the threaded nut. The portion of the strip extending beyond the head of the threaded fastener is bent into a groove in the surface of the head of the threaded fastener, preventing accidental disassembly of fastener and nut.