Best 7/8 Flat Washers for Matching Bolt Size and Outside Diameter
The best 7/8 flat washer depends on whether 7/8 inch refers to the bolt size or the washer’s outside diameter. For a 7/8-inch fastener with a large 1-3/4-inch outside diameter, compare the 304 stainless options and the steel SAE set below. If you need a washer with a 7/8-inch outside diameter, the final two products are smaller washers with a 3/8-inch inside diameter—not replacements for a 7/8-inch bolt washer.
| Product | Best For | Key Detail |
|---|---|---|
| 12-piece 304 stainless set | Several large washers | 7/8-inch listing; 1-3/4-inch OD |
| SAE steel set | Steel washer requirements | 7/8-inch listing; 1-3/4-inch OD |
| 5-piece 304 stainless set | Small stainless quantity | 7/8-inch listing; 1-3/4-inch OD |
| 50-piece 3/8-inch set | 3/8-inch fasteners | 7/8-inch OD |
| 100-piece 3/8-inch set | Bulk 3/8-inch washers | 7/8-inch OD |
12-Piece 304 Stainless Steel Flat Washers
Best for: Buyers who need multiple large stainless washers for a 7/8-inch fastener application. This set includes 12 silver 18-8 (304) stainless steel washers, with a stated outside diameter of 1-3/4 inches and thickness of 0.11 inch.
The listed inside-diameter range is 0.931 to 0.968 inch. Check that measurement against your bolt and project requirements rather than assuming every product labeled 7/8 inch has the same hole size. The 12-piece quantity makes this a practical choice when a small set is not enough.
Limitation: The listed inside diameter is a range, so verify fit before ordering if a close tolerance matters.
SAE Steel Flat Washers, 10 Pieces
Best for: Buyers seeking a steel option rather than stainless steel. The listing identifies the material as steel and gives dimensions of 7/8 inch and 1-3/4 inches. It comes as a 10-piece set, making it a middle-ground quantity compared with the five- and 12-piece stainless selections.
Choose this set if its listed dimensions and steel material suit the job. The product name identifies the washers as SAE flat washers, but the available details do not specify coating, thickness, or corrosion resistance.
Limitation: Avoid this option where stainless material is specifically required; the provided listing describes it simply as steel.
Five 304 Stainless Washers, 1-3/4-Inch OD
Best for: Buyers who want a small quantity of 304 stainless washers. The listing specifies five pieces, a 7/8-inch inside diameter, and a 1-3/4-inch outside diameter. It describes the washers as 18-8 (304) stainless steel and highlights corrosion resistance as a product feature.
Choose this set when the stated dimensions match your fastener and you do not need a larger pack. It offers fewer pieces than the 12-washer option, which may suit a limited repair or assembly.
Limitation: The package contains only five washers, so it may not suit jobs requiring a larger quantity.
50-Piece 3/8-Inch Stainless Washer Set
Best for: Buyers who mean a washer with a 7/8-inch outside diameter and need it for a 3/8-inch fastener. The product name gives dimensions of 3/8 inch inside diameter by 7/8 inch outside diameter, with a thickness of 0.078 inch. It lists 50 pieces and 18-8 (304) stainless steel.
This is not a 7/8-inch bolt washer. Choose it only if the required measurement is the outside diameter and the 3/8-inch hole matches your fastener.
Limitation: Its 3/8-inch inside diameter makes it unsuitable for a 7/8-inch bolt.
100-Piece 3/8-Inch Stainless Flat Washers
Best for: Buyers who need a bulk supply of washers for 3/8-inch fasteners and want a stated 7/8-inch outside diameter. The listing identifies 100 pieces and 304 stainless steel. This larger quantity is the main distinction from the 50-piece option.
Choose this set for repeated projects where the 3/8-inch hole and 7/8-inch outside diameter fit the application. It should not be treated as a 7/8-inch inside-diameter washer.
Limitation: The provided product details do not specify washer thickness.
Buying Guide: How to Choose a 7/8 Flat Washer
Does 7/8 Inch Mean Inside Diameter or Outside Diameter?
Confirm which dimension your project requires. A washer listed for a 7/8-inch fastener typically has an inside hole sized for that application, while a washer described as 3/8 inch by 7/8 inch has a 3/8-inch inside diameter and 7/8-inch outside diameter. The two sizes are not interchangeable.
Which Material Should You Choose?
Choose stainless steel when the listed 304 or 18-8 material suits your environment and application. Choose the steel SAE option if steel is required, but check the complete product specification when coating, corrosion behavior, or thickness matters. Do not infer unlisted material properties from a product title alone.
How Many Washers Do You Need?
Compare package quantity with the number of fasteners in the project and whether you want extras. The relevant large-washer options come in packs of five, 10, and 12. The 3/8-inch washers come in packs of 50 and 100, but their dimensions make them appropriate for a different fastener size.
What Dimensions Should You Verify?
Check inside diameter, outside diameter, and thickness against the hardware and the surface being clamped. A larger outside diameter spreads contact across a wider area, but it must fit the available space. When exact fit is important, use the stated measurements rather than relying only on the nominal washer size.
Frequently Asked Questions
What does a 7/8 flat washer size refer to?
It can refer to a washer intended for a 7/8-inch fastener or, in some product descriptions, a 7/8-inch outside diameter. Read the inside and outside diameter specifications to distinguish them.
Is a 3/8-inch-by-7/8-inch washer suitable for a 7/8-inch bolt?
No. That dimension format identifies a 3/8-inch inside diameter and a 7/8-inch outside diameter, so it is intended for a smaller fastener.
What is the outside diameter of the listed large washers?
The stainless options and the SAE steel option list a 1-3/4-inch outside diameter.
Which listed option has the largest quantity?
The 3/8-inch stainless washer set contains 100 pieces. It is a bulk option for 3/8-inch fasteners, not 7/8-inch fasteners.