SAE Flat Washers

SAE Flat Washers
Zinc Plated Steel

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SAE Flat Washers fit tighter on a Bolt than a USS Flat Washer, as they have a smaller I.D. (Internal Diameter).

The O.D. (Outer Diameter) of a SAE Washer is also smaller than that of a USS Flat Washer.

Size

O.D.

I.D.

Thickness

# per Lb. (approx.)

#4

5/16

1/8

1/32

1666

#6 (1/8)

3/8

5/32

3/64

790

#8 (5/32)

7/16

3/16

3/64

590

#10 (3/16)

1/2

7/32

3/64

455

#12

9/16

1/4

1/16

294

1/4

5/8

9/32

1/16

222

5/16

11/16

11/32

1/16

195

3/8

13/16

13/32

1/16

140

7/16

59/64

15/32

1/16

110

1/2

1-1/16

17/32

3/32

56

9/16

1-3/16

19/32

3/32

45

5/8

1-5/16

21/32

3/32

37

3/4

1-1/2

13/16

9/64

21

7/8

1-3/4

15/16

9/64

15.5

1"

2"

1-1/16

9/64

11.7

1-1/8

2-1/4

1-3/16

9/64

9.2

1-1/4

2-1/2

1-5/16

5/32

6.7

1-3/8

2-3/4

1-7/16

5/32

5.5

1-1/2

3"

1-9/16

5/32

4.6

Key Features and Benefits of SAE Flat Washers

SAE flat washers are precision-engineered fasteners designed to meet Society of Automotive Engineers specifications for consistent performance across industrial applications. These washers feature a smaller outside diameter compared to USS flat washers, making them ideal for applications where space constraints require compact load distribution solutions. Manufactured primarily from low carbon steel, SAE washers provide reliable strength while maintaining cost-effectiveness for high-volume projects. Automotive engineers frequently specify SAE flat washers for their precise outer diameter tolerances and consistent thickness specifications. The standardized diameter ensures proper fit with corresponding bolt sizes, preventing over-drilling and maintaining structural integrity. These washers excel in applications requiring uniform load distribution across bearing surfaces, making them essential components for automotive, machinery, and general industrial fastener assemblies.

Coatings and Finishes for Corrosion Resistance

SAE flat washers are available with various protective coatings to enhance durability and extend service life in challenging environments. Zinc plating is the most common finish for low carbon steel SAE washers, providing excellent corrosion resistance at economical cost. Stainless steel options eliminate the need for additional coatings while offering superior corrosion resistance for marine and food-grade applications. Hot-dip galvanizing provides heavy-duty protection for outdoor and industrial applications where washers face harsh environmental conditions. Black oxide finishes offer basic corrosion protection while maintaining a professional appearance. The coating selection depends on specific application requirements, with automotive engineers often choosing zinc-plated options for standard automotive applications. Proper coating selection ensures SAE flat washers from Nutty maintain their load distribution capabilities throughout their service life while protecting the underlying bolt and substrate materials.

FAQ

SAE flat washers are available in standard sizes from #6 through 3 inches, following Society of Automotive Engineers specifications. Common sizes include 1/4", 5/16", 3/8", 1/2", 5/8", 3/4", and 1". Each size features precise outer diameter and thickness dimensions that differ from USS flat washers, with SAE washers having smaller outside diameter specifications.

SAE flat washers are commonly used in automotive, machinery, and general industrial applications where precise load distribution is required. Automotive engineers specify them for vehicle assembly, engine components, and chassis applications. Their smaller outside diameter makes them ideal for tight spaces while still providing adequate bearing surface for proper bolt performance.

The primary difference between SAE washers and USS washers is the outside diameter specification. SAE flat washers have a smaller outside diameter compared to USS flat washers of the same bolt size. USS washers follow United States Standard specifications with larger outer diameter for increased bearing surface, while SAE washers prioritize compact design.

Yes, SAE flat washers are available with various coatings including zinc plating, hot-dip galvanizing, and black oxide finishes. Stainless steel options provide inherent corrosion resistance without additional coatings. Special coatings enhance durability for specific industrial applications while maintaining the precise diameter and thickness specifications required for proper load distribution and bolt performance.

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