Types and usage of self-locking fasteners


Self-locking fasteners are developed to prevent the loosening of the screws due to shock or any other external forces. Fasteners are used to avoid the chances of disassembling of screws and bolts. The fasteners are designed and installed in such a way that the possibility of disassembling of nuts and bolts reduces to a minimum.

How do self-locking fasteners work?

The standard fasteners get to lose as soon as they get a shock. These fasteners vibrate out leading to the loosening of the screw. The self-locking fasteners prevent the loosening of the nuts and bolts as they are designed, engineered and installed properly.

Alternatives of self-locking fasteners

There are many alternatives to self-locking fasteners, which include cotter pins, jam nuts, washers, and many other similar devices. These devices also prevent the disassembling of nuts and bolts. The disadvantage is that these devices add extra weight to the nuts and bolts. These alternatives are also rejected because of the insecurity of conventional mechanical locks.

Types of self-locking fasteners

There are many types of self-locking fasteners, which can be used at different places for different purposes. These types have been discussed here.

Chemical additive type

This self-licking fastener can be applied in two ways. These ways include pre-applied and applied-in-place. Lower assembly torque of this fastener functions because of solid fill from the adhesive coating. Both the ways of application are reliable in fastening the nuts and bolt. However, the in-place ones can be used only one time while the applied-in-place can be used for multiple times.

Prevailing torque type

This is the only fastener that has the property of retaining its locking torque. This fastener is free from axial load. When the nuts and bolts get a shock, there is a chance of loosening; the fastener prevents the process of loosening. There are two types of prevailing shock fasteners, which are material additive type and deflected or distorted thread type.

Deflected or distorted thread type

These fasteners can be reused but to a limited extent only. These fasteners are designed to regular the thread conformity from loosening. These fasteners depend on the type of hole for which they are being used. These fasteners are designed very carefully and their size is 0.312. If the size is greater than this, it can result in galling because of the distorted threads.

Material additive type

These fasteners are developed with mating threads that are wedged near each other. The fastener locks the device in the circumferential direction by dragging metal to metal.

Wrapping Up

These are some of the fatteners and their usage. People can purchase them and use them to prevent the loosening of the nut and bolts. Each faster has a different technique of locking the nuts and bolts. Some of them work well and are reusable while others can be used only once.