What Is the Purpose of a Lock Washer?

Washers are offered in every sort of shapes and size. Each washer category has its own unique function. Lock washers, they are designed to keep nuts and bolts from coming movable. Lock washers have their own variety of models. Every is intended for use in a particular application. Some lock washers look like rings with uneven terminations. Others appear star shaped with an outer ring of teeth.

Locking Washer Function

The lock washer stops nuts and bolts from turning, slipping & coming loose because of vibration and rotation. Unusual lock washers execute this function in somewhat different ways, but the introductory conception is to hold the nut and bolt in place. Some lock washers achieve this function by smelling into the base material (bolt) and the nut with their terminations.

Types of Lock Washers

A helical lock washer (also called a “split washer”) looks like a ring with uneven ends. The ends of the ring bite into fastener material to keep it from turning. Internal-tooth lock washers have teeth placed on the inside of the ring and offer a good connection with tiny fastener heads.

External-tooth lock washers (also called “star washers”) have teeth located on the outside of the washer ring, and they work well with big fastener heads. External-Internal/Combination lock washers have teeth on both the inside and outside of the ring. This gives better security with large fastener heads.

Pyramidal-kind lock washers are used for projects requiring high-tightening torques. Countersunk lock washers are used with flat or oval head screws having either 82 or 100-degree countersunk angles.

Dome-type lock washers distribute the load over a wide area and are optional for use with thin or soft materials that require high torque for holding.

Dish lock washers are similar to domed lock washers but might be used in applications requiring less torque or load.

Most Common Materials

Most lock washers are comprised of aluminum, stainless steel, K-Monel, bronze, zinc, phosphor bronze alloy, and carbon steel. The material used in manufacturing the lock washer is significant in precluding it from breaking-up,  thereby losing its fastening strength.

Locking Washer Applications

Lock washers are usually used in operations involving vibration and possible slippage of fasteners. Industries that generally use lock washers are transportation-related (automotive, aircraft, marine). Lock washers might also be used in household purposes similar as air handlers and clothes washers (washing machines).


If too much rotation is applied to a helical lock washer, it can flatten out and become a regular washer, thereby losing its locking capability. Furthermore, lock washers must not be used as a method to secure a bolt or nut too small for a hole in the part being secured. They must also not be used to strain a bolt or nut that’s too long.