What is a Lock Washer

  • Release date:31-01-2017
  • Abst:

    Washers are thin, round pieces of metal with a hole for […]

    Washers are thin, round pieces of metal with a hole formed in the center. Commonly placed on the end of a bolt to separate a nut from the surface from which the bolt is extending, washers provide a surface that the nut can tighten against. Lock washers can also be placed next to the head of a bolt to secure it in place when tightened. You can use lock washers to lock the nut in place as it is tightened down on the bolt too. Installing a lock washer can help prevent the nut from working loose during use.

    Threaded connections between two or more objects typically involve the use of a screw, or bolt and a nut. Lock washers are used for threaded connections using a screw and nut combination. The screw has a large head on one end and a shaft with an external thread, which is a helical structure that allows the screw to be advanced when rotated. The nut, which is usually hexagonal in shape, has a hole with an internal thread that matches the thread of the screw.

    When a screw is inserted and rotated into a nut, the screw advances. A significant force can be generated when the screw and nut are tightened against two or more objects located between the screw head and nut surfaces. Users put the lock washer between the nut and its surface becomes secured or joined. It resists the force being applied by the nut and prevents the nut from loosening.

    A split lock washer has a donut shape — a circle with a hole in the center — and has a single cut which extends from the outside diameter to the inside hole. The cut is the reason this type of washer is called a split lock washer. The two sections adjacent to the cut are misaligned in the direction perpendicular to the washer surface. This misalignment allows the lock washer to resist force by creating friction through resulting spring action that prevents the nut from loosening.

    In addition to resisting force through friction, the shape of certain types of lock washers can cause them to bite into the mating surface and create a mechanical grabbing force. Star lock washers have internal and external teeth, and each adjacent tooth is bent in alternating directions perpendicular to the washer surface. The teeth bent to one side embed themselves into the nut, while the teeth bent in the opposite direction embed themselves into the work surface being fastened. Same as tab lock washers, they have bent tabs at the edges that mate with the surface of the nut, and lock the nut in place.

    Removing the lock washer could be as simple as giving it a tug, or you may need to work it a bit and get some help from a lubricant if the teeth have dug in.
    Remove the nut from the bolt using a socket or adjustable wrench.

    Pull the lock washer off, using the flat head screwdriver gently wedged in beside the washer to get it started if you need to.
    Use the screwdriver to work around the circumference of the lock washer to loosen it if the lock washer is still stuck. Work it off the bolt gently.
    You should put lubricant into the joint and wait for a moment. Then try again to loosen the lock washer with the screwdriver and pull it off.
    Work the screwdriver under the teeth of the lock washer if it has teeth and is still stuck. The teeth can bite into the bolt, jamming the washer. You should be careful that don’t destroy the threads on the bolt. If it is still stuck, try spraying more lubricant under the teeth of the lock washer and trying again. click to see more information.