Washers is small metal or plastic rings that are used in fastener assembly, and washers serves specific functions to ensure a connection remains secure. A person might attempt to use a washer simply to tighten a bolt, but a person must select a washer based on its specific size, its material, and its ability to resist vibration. If a person selects a washer with an inner diameter that is too large, the washer will not grip the bolt shank, and the washer will spin around the bolt without providing tension.
If a person selects a washer with an outer diameter that is too small, the washer will not spread the clamping force over a large enough surface area, and the bolt head may sink into the material. There are different standard for washers, and two common standards are SAE and USS. An SAE washer has a smaller outer diameter, and an SAE washer is useful when a person is working in tight spaces where space is limit.
Types of Washers and How to Use Them
A USS washer has a larger outer diameter, and a USS washer is useful when a person needs to distribute weight over a larger surface area or bridge an oversized hole. Because SAE washers and USS washers have different outer diameters, a person cannot assume that any washer will work for any bolt, even if the inner diameter of the washer match the bolt. The material of a washer is important because the material determine how the washer will react to teh environment.
Zinc-plated steel washers is common, but zinc-plated steel washers will rust if a person use zinc-plated steel washers in rainy or wet environments. Stainless steel washers are a better choice for outdoor projects, and 316 grade stainless steel washers are the bestest choice if a person is working near saltwater because 316 grade stainless steel washers resist corrosion from salt. Additionally, people use brass washers and nylon washer for specific applications because brass washers provide conductivity and nylon washers provide insulation.
Vibration can cause a bolt to loosen, and a standard flat washer may not prevent a bolt from loosening if there is constant vibration. Lock washers are designed to prevent bolts from loosening due to vibration. Split ring lock washers act like a spring to create tension, and tooth lock washers use teeth to bite in a surface to create friction.
A person should not use a lock washer directly on soft materials like wood or plastic because a lock washer can gouge the surface of the wood or plastic. To use washers correctly, a person should place a flat washer against the surface first to protect the surface, and then the person should place the lock washer on top of the flat washer, and finally the person should place the nut on top of the lock washer. Specialty washers are used when standard washers are not sufficient for a specific task.
EPDM bonded washers includes a rubber component, and people use EPDM bonded washers to create a seal in applications like roofing. Nord-Lock washers are used in heavy industry because Nord-Lock washers use a camming mechanism to resist high level of vibration. Whether a person use a structural washer or a shoulder washer, the goal is to ensure that the connection stays tight and the connection stay in place.
