Flat washers are one of the most commonly used fastener accessories in industrial and consumer applications. While they may appear simple and straightforward, there is a lot of variety in the types and sizes. In general, however, there are two main categories of flat washers: SAE and USS.

So, what’s the difference between SAE and USS flat washers? Here, we’ll look at the two types of flat washers, their main differences, and when to use each.

What are SAE Flat Washers?

SAE WasherSAE flat washers are the most common type of flat washer. They are also sometimes known as standard washers. These washers are made to meet the standards set by the Society of Automotive Engineers (SAE).

These washers are generally small, with an outer diameter (OD) that is typically more than 1 1/2″. However, the thickness can vary quite a bit, depending on the size of the bolt or screw. SAE flat washers are made from various materials, including steel, brass, and bronze.

What are USS Flat Washers?

SAE vs. USS Flat WashersUSS flat washers are a type of flat washer used in applications where a more secure fit is required. They get their name since they were first used by the United States Navy (USS stands for United States Standard).

USS flat washers are the largest among all flat washers. They have a greater outer diameter (OD) and are thicker than SAE flat washers. As a result, they can provide a more secure grip and prevent loosening due to vibration. USS flat washers are also made from various materials, including steel, brass, and bronze.

Because of the oversized design, USS flat washers are not typically used with smaller screws and bolts. They are more common in industrial applications where larger fasteners are being used.

When to Use SAE vs. USS Flat Washers?

As a general rule, SAE flat washers are best for most applications. They are strong and durable yet relatively small and easy to work with. But, sometimes, USS flat washers may be the better option.

For instance, if you are working with large fasteners or bolts subject to a lot of vibration, then USS flat washers can provide a more secure grip. Also, if you need to protect the surface of the material you are fastening (such as in a woodworking project), then USS flat washers can help to distribute the load more evenly.

Ultimately, choosing the right type of flat washer for your specific application is essential. Be sure to consider the size of the bolt or screw, the amount of force or stress, and the materials involved.

At Minneapolis Washer and Stamping, we offer SAE and USS flat washers in various sizes and materials. Also, we can custom manufacture washers to meet your specific requirements. Place your order today!

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