Applications for Washers
Washers come in many types and are used for a wide variety of applications. These disks, which are made of metal or non-metallic materials, are positioned underneath a nut, an axle bearing or a joint to mitigate friction, isolate components, prevent loosening, eliminate leakage or distribute pressure. They also help secure fasteners.
The metallic materials used to fabricate washers include stainless steel, titanium, aluminum, brass, copper-base alloy or bronze, copper, nickel-base alloy, spring steel, steel, hardened steel and zinc-plated washers.
The non-metallic materials of construction include rubber, ABS, asbestos, felt, leather, nylon, polyester, polycarbonate, polyethylene, PVC, polypropylene, PTFE and Mylar.
Types of Washers
There are many different types of washers, which manufacturers have designed for use with a wide variety of applications. Spring washers consist of a load-bearing apparatus, which provides a preload between two surfaces. Lock washers help secure fasteners.
Other common types of washers include:
•Countersunk (finishing) washers
Specialty washers include copper sealing washers that are designed to seal with a certain force against the mating surfaces. Bonded sealing washers create a seal that provides a greater degree of corrosion protection than conventional washers do. Neoprene bonded seal washers are soft and resilient, but create an excellent bond to the metal washer, and forms a tight seal. This washer can be used to seal out air/water or dampen vibration and noise. A neoprene bonded seal washer is perfect for use with fragile materials that require some additional cushioning under a screw, head of a bolt or screw and preventing leaks by sealing joints.
Sealing washers help seal joints, prevent leakage and provide cushioning under the head of the bolt or nut. Bonded washers are used in combination with a gasket. Rubber bonded washers are fabricated to very precise standards. The washer ensures a perfect fit because the rubber material will not slip. A rubber bonded washer has excellent resistance to cleaning agents and fuel residue.
The thickness and height of your washer represents important design considerations, because the values describe the axial cross-section and working height of a spring washer. Zinc-plated bonded washers and other washers typically reference a gauge thickness value, which consists of the standardized dimension in the industry for tube and strip steel products. For example, a bonded washer with the gage number 0000 would have a thickness of 0.500”, while a washer with a gauge number of 36 would have a thickness of 0.004”
When specifying the dimensions of washers, most people use the nominal ANSI sizes and refer to the size of the fastener that the washer is designed to mate with. The nominal ANSI values used to describe the size of the washer should represent the inner diameter of the washer as closely as possible. Keep in mind that the outside dimension of the washer is always larger.