3.1.5.1.1 Conventional fastening methods

Those conventional methods used in the assembly industry are flat washer, spring washer, nylon lined nut, serrated bolt, etc.

They have shortcomings such as the following: they loosen under vibration, thermal expansion, and/or plastic deformation, they do not seal thread as the space between bolt and nut is all empty, they require extensive inventory of several fastener shapes and sizes, they are prone to rust and damaged surface due to empty space and poor handling, they have a wide bolt tension scatter as each bolt assembled with the same tightening torque shows a different bolt tension on a flange, they show lower break loose torque than tightening torque resulting in unstable assembly, and they are more costly than liquid thread locking adhesive [3].
