A washer is a thin disk-shaped plate with a hole in the middle that is used to distribute the load of a threaded fastener, such as a screw or nut. Other uses for washers are as a spacer, spring, wear pad, preload indicating device, locking device or in the case of a rubber washer, to reduce vibration.
USS Flat Washers
Rather than being geared towards one specific industry, United States Standard (USS) flat washers were developed to satisfy engineering requirements for general industrial applications such as manufacturing, maintenance and repair. Click here to buy USS flat washers online.
SAE Flat Washers
SAE flat washers were designed by the Society of Automotive Engineers specifically for broad usage within the automotive industry. These washers generally have a smaller outer diameter (OD) and come in thinner gauges and thicknesses than USS flat washers, so as to be very versatile within automotive applications. Click here to buy SAE flat washers online.
Fender washers are flat washers with a thinner body and increased outer diameters, which offers a greater surface bearing. These washers are used when a large outer diameter is required for larger bearing surface or surface load reduction. Fender washers are commonly used in auto body repair, sheet metal fastening, and plumbing and electrical trades. Click here to buy fender washers online.
Split Lock Washers
Split lock washers, sometimes called helical spring lock washers, look like a ring with uneven ends. The “split” in the washer absorbs initial driving torque and then closes under nominal bolt loading. It then provides resistance to the back-off rotation of the screw when tension in the assembly is reduced and loosening occurs. Click here to buy split lock washers online.
External Tooth Lock Washers
External tooth lock washers are designed to prevent a nut or bolt head from loosening with the strut action of the teeth. They work best with larger screw or bolt heads, such as round or pan head. These washers provide maximum torsional resistance. Click here to buy external tooth lock washers online.
Internal Tooth Lock Washers
Like external tooth lock washers, internal tooth lock washers also prevent but or bolt head loosening by way of the teeth's strut action. In addition to absorbing shock and vibration, the teeth also abrade grounding surfaces in electrical grounding applications, thereby improving electrical connections.
Finishing washers are used in applications where appearance is of high importance, protecting the underlying material that the washer is covering. A flat head screw is recessed into the finishing washer, creating a clean, flat surface in outward appearance.
Torque washers feature sharp prongs designed to sink into the mating surface, thereby preventing any rotation between the washer and the mating surface. For this reason, torque washers are also referred to as "anti-turn" washers.
Special washers called such due to their non-circular inside or outside shapes. Some of the common special washers include C-shapes, D-shapes, rectangular, square, hexagonal hole, square hole and more.