A Further Form of deflected thread interference, again operating on the flanks of the form. 

Both of these systems provide prevailing torque properties by forcing the fastener threads into close contact with the mating form. 

Their efficiency does, however, rely on a smooth lead-in being provided on the mating thread.

If this condition is not present the nylon can be sheared off instead of deformed and a loss of interference for repeated applications and have no tendency to damage the mating
thread. They are not however,suitable for high temperature
applications.

Longlok Above

Wedgelok Above

The present day equivalent of the wedgelok and Longlok systems are the coated or patch types, such as Eslok, Locwel and Circloc.

The Eslok method employs a patch of powdered nylon fused to the threads of the fastener. The 'Locwel' has a strip of nylon adhesive bonded onto the thread form and the 'Circloc' has a spiral band wrapped around.

Whiz-Tite Locking, underside or bearing surface has a series of spiralling serratims or teeth whose shape, height and radius produce a high break loose torque.

The Convex angle of the base further improves the locking effectiveness of the teeth.