Types of Washers

A type of fastener, washers are thin disk-shaped plates with a hole in the center, used in conjunction with a threaded fastener such as a screw or bolt. Washers distribute load, create separation, prevent corrosion and wear, lock fasteners into place, and reduce vibrations. Washers are typically made from metal or plastic, although rubber and fiber are used as well in limited applications. Washers vary in size, but typically have an outer diameter roughly twice that of the inner diameter.

Washers come in three basic categories: plain, spring, and locking.

Plain washers, or flat washers, have a flat annulus or ring used to spread the load of a screwed fastener, and prevent damage to the surface being fastened. These include penny washers, which have a larger outer diameter proportional to the central allowing it to distribute loads more evenly, or c-washers that can be slid in and out of position on the bolt or shaft.

Spring washers are a type of washer with axial flexibility that helps prevent fastening or loosening as a result of vibrations or shock. Spring washers include Belleville washers, which have a conical shape which helps maintain tension in assemblies that experience frequent thermal expansion and contraction, wave washers which feature a “wave” in the axial direction that makes it suitable for use as a cushion spring or spacer, and split washers that feature a ring split at one point and bent into a helical shape to create more friction and rotation resistance.

Lastly, locking washers are often interchangeable with spring washers, and prevent fastening or loosening rotation. Types of locking washers include helical springs that increase the pre-load on the fastener while tightening, which provides protection against loosening, toothed lock washers that feature serrations around the edge that can extend inward and outward to bite into the surface material and provide maximum torsional resistance, and tab washers that feature a side tab that can be bent into place against a nut, preventing rotation.

At Fulfillment3Sixty, owned and operated by ASAP Semiconductor, we can help you find all the washers and fasteners for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@fulfillment3sixty.com or call us at 1-714-705-4780.