Round plate washers are simply a low carbon steel, oversized cut washer designed to provide a larger bearing surface than an F844 standard flat washer.
Plate washers are commonly used in wood construction to prevent bolt heads or nuts from pulling into the wood. Square plate washers are also available. A plate washer is used in a variety of projects including: marine and timber.
Stock
Diameters: 1/2″ – 1″
Origin: Import
Finish: Plain and hot-dip galvanized
Dimensions
| Bolt Size | B | A | C | Weight (lbs.) Per 100 Pieces | Part Numbers | |
|---|---|---|---|---|---|---|
| Outside Diameter | Inside Diameter | Thickness Gauge | Plain | Galvanized | ||
| 1⁄2 | 21⁄4 | 9⁄16 | 3⁄16 | 20 | 19277 | 19278 |
| 5⁄8 | 21⁄2 | 11⁄16 | 1⁄4 | 32 | 19279 | 19280 |
| 3⁄4 | 3 | 13⁄16 | 1⁄4 | 46 | 19281 | 19282 |
| 7⁄8 | 31⁄2 | 15⁄16 | 5⁄16 | 79 | 11961 | 11962 |
| 1 | 4 | 11⁄16 | 3⁄8 | 124 | 11963 | 11964 |
| 11⁄4 | 5 | 13⁄8 | 3⁄8 | 193 | 12610 | 12611 |
| 11⁄2 | 6 | 15⁄8 | 3⁄8 | 184 | - | - |
FAQs
A round plate washer is a low-carbon steel, oversized washer that provides a larger bearing surface than a standard F844 flat washer. Its increased diameter and thickness help distribute load more effectively, preventing the bolt head or nut from embedding into wood or softer materials. Round plate washers are essential in heavy timber and marine construction, where structural strength and resistance to pull-through are critical.
Round plate washers are primarily used in wood, timber, and marine construction. They are often paired with anchor bolts, timber bolts, or square head bolts to reinforce joints and prevent fastener heads or nuts from sinking into the wood. Typical applications include piers, docks, timber bridges, boardwalks, and heavy framing assemblies. Their simplicity, strength, and large bearing area make them a reliable choice for both structural and restoration projects.
The main difference between a round plate washer and a standard flat washer (F844) is size and thickness. Plate washers are larger in diameter and heavier-gauge, offering significantly more load-bearing capacity. While standard flat washers are used for general-purpose fastening, round plate washers are designed for high-stress applications where the connection must resist wood crushing, pull-through, or long-term loosening caused by environmental conditions.
Round plate washers are highly effective in reinforcing wood connections. Their oversized bearing surface distributes the applied load evenly, reducing the likelihood of the bolt or nut compressing into the timber. This helps maintain structural alignment and prolongs the life of the joint. In marine and outdoor structures, galvanized plate washers also provide corrosion resistance, ensuring that connections remain secure despite exposure to moisture and changing weather conditions.
Portland Bolt supplies round plate washers in diameters from ½″ through 1″, available in multiple finishes to suit different applications:
- Material: Low-carbon steel
- Finish: Plain or hot-dip galvanized
- Origin: Import
Hot-dip galvanized washers are ideal for outdoor and marine use, while plain steel washers are suitable for indoor or protected environments.
While both types of washers provide the same primary function, distributing load across a larger bearing surface, they differ in shape, appearance, and common usage. Round plate washers feature a smooth, circular profile, which gives them a more refined appearance and makes them well-suited for projects where symmetry and aesthetics matter, such as exposed wood framing, boardwalks, or dock surfaces.
In contrast, square plate washers provide slightly more surface coverage per unit area, making them a preferred choice for heavier structural or seismic applications where maximum bearing strength is required. Ultimately, the selection between round and square plate washers depends on engineering specifications, environmental conditions, and design preference, with both styles offering reliable load distribution and reinforcement for wood and marine construction.
Round plate washers are versatile and can be used with a variety of headed bolts and rods, including:
- Anchor bolts in concrete-to-timber connections
- Timber bolts in dock and bridge construction
- Square head or hex head bolts in heavy wood framing
Their large bearing area makes them particularly useful anywhere the bolt head or nut bears directly on wood and requires reinforcement against pull-through.
Round plate washers are typically manufactured from low-carbon steel, suitable for structural applications that do not require high tensile strength. They are not covered by a specific ASTM washer standard like hardened steel washers (e.g., F436), but are commonly supplied to ASTM A36 material specifications for general-purpose steel plate components. When galvanized, they conform to ASTM F2329 for coating integrity and corrosion protection.
Yes. When hot-dip galvanized, round plate washers perform exceptionally well in marine, dock, and outdoor environments. The zinc coating provides a long-lasting protective barrier against rust and corrosion, ensuring reliable performance even in saltwater or high-humidity conditions. Their combination of strength and durability makes them ideal for coastal and waterfront construction projects.
Portland Bolt supplies high-quality plate washers that meet industry standards and project specifications, ensuring reliable performance in structural applications. With both plain and galvanized options, fast lead times, and the ability to provide custom-cut washers, Portland Bolt delivers washers that meet the rigorous demands of marine, timber, and infrastructure construction projects.