Fair Wind Fasteners
Silicon Bronze Hex Flange Nut
Silicon Bronze Hex Flange Nut
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651 Silicon Bronze Serrated Hex Flange Nuts
Marine Grade | UNS C65100
Secure your build with confidence using our 651 Silicon Bronze Serrated Hex Flange Nuts—the premium fastening choice for high-strength, corrosion-resistant applications in marine and coastal environments. Precision-machined from UNS C65100 silicon bronze, these flange nuts are trusted by boatbuilders, shipyards, and restoration professionals who demand uncompromising durability and performance.
Key Features:
- Material: 651 Silicon Bronze (UNS C65100)
- Integrated Flange: Distributes load evenly and eliminates the need for a washer
- Serrated Bearing Surface: Locks in place and resists vibration-backed loosening
- Thread Type: Unified National (Imperial)
- Corrosion Resistance: Outstanding in saltwater and high-moisture environments
Why Choose These Nuts?
Unlike standard flange nuts, the serrated face bites into mating surfaces, providing a mechanical lock that resists loosening due to vibration or torque cycling. Paired with a silicon bronze bolt or machine screw, these nuts form an unbeatable union that won't gall, seize, or degrade like stainless steel can in wet or dissimilar-metal conditions.
Common Uses:
- Wooden boat construction and refits
- Deck hardware installations
- Coastal architectural projects
- Outdoor furniture and copper sculpture assembly
- Anywhere vibration resistance and long-term corrosion performance are critical
Bronze Flange Nut Dimensions:

Size | Flange Diameter (FD) | Total Height (TH) |
1/4"-20 | ||
5/16"-18 | 0.659" | 0.275" |
3/8"-16 | 0.725" | 0.340" |
1/2"-13 | 1.022" | 0.455" |



This is my third order with Fairwinds fasteners, and it certainly won’t be my last.
Quality products in stock, love the packaging, especially the little muslin sac parts arrive in.
Highly recommended!
Best place to buy quality bronze fasteners!
I'm very happy. Very nice high quality flange nuts . Bought with additional mating hardware that was of the same quality. Came package in labeled pouches which ia a very nice touch!