SAE Flat Washers

SAE vs USS flat washers

SAE and USS are two dimensional patterns, and the difference is size. For a given inside diameter, an SAE washer has a smaller outer diameter and thinner body than a USS washer, giving a tighter fit that suits automotive, machinery, and any assembly where space is limited or a large washer would interfere. SAE washers are also the recommended choice under Grade 5 and Grade 8 hex cap screws. Choose SAE for a compact, precise fit, then choose the finish or grade for the environment and load, from economical zinc to thru-hardened Grade 8 for high-strength joints.

Finish and grade choices for SAE washers

• Zinc plated: economical corrosion resistance for indoor and dry use.
• Low carbon plain steel: bare economical washer for coated assemblies.
• Grade 8 thru-hardened: high-strength washers for high-load bolts.
• 316 stainless and black chrome: marine corrosion resistance and dark decorative finish.

Common applications for SAE flat washers

• Automotive and machinery assembly
• Tight-clearance and precision work
• Grade 5 and Grade 8 bolted joints
• General fastening where a compact washer fits best

For a wider, thicker pattern, see USS flat washers, and browse every option on the main flat washers category.

SAE Flat Washers FAQ

What is the difference between SAE and USS washers?

For a given bolt, an SAE washer has a smaller outer diameter and thinner body than a USS washer, giving a tighter, more compact fit for automotive and tight-clearance work.

When should I use an SAE washer?

Use SAE for automotive, machinery, and tight-clearance work, and any time the assembly uses Grade 5 or Grade 8 cap screws. USS suits construction and larger fasteners.

Do SAE washers have a strength grade?

Plain SAE washers are a dimensional pattern without a defined grade. For high-strength joints, choose a thru-hardened Grade 8 SAE washer.