1/2"-13 x 3-1/2" Grade 8 Carriage Bolts (10-Pack) – Heavy-Duty Coarse Thread Bolts with Washers and Nylon Lock Nuts – Round Head Square Neck SAE J429 3.5" Black Finish — Open-Box, 9% Off

Name: 1/2"-13 x 3-1/2" Grade 8 Carriage Bolts (10-Pack) – Heavy-Duty Coarse Thread Bolts with Washers and Nylon Lock Nuts – Round Head Square Neck SAE J429 3.5" Black Finish
Brand: Quantum Forge
SKU: awhd-us-b0h8x1ycf7
Price: 30.04 USD
Availability: InStock

Brand: Quantum Forge

Condition: Used - Mint

$30⁰⁴

$32⁹⁴

-9% Save $2⁹⁰

Updated: 12 days ago

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Description

Complete 10-packs: Includes 10 Grade 8 carriage bolts, 10 hardened 1/2" washers, 10 1/2"-13 nylon lock nuts. Bolts 1/2" diameter x 3-1/2" long. Plain Black finish on bolts and nuts, yellow zinc on washers.

Smooth round head with square neck – Features a domed, low-profile head and square shoulder that locks into wood or other materials to help prevent bolt rotation during tightening, allowing installation with a single wrench.

Grade 8 Strength for Demanding Jobs: High-tensile SAE J429 Grade 8 bolts deliver superior load capacity and shear strength. Threads are made to the requirements of ASME B1.1. ASME B18.5 Dimensional Requirements. SAE J429 Material and Strength Level. ASTM F788 Surface Discontinuities. ASME B18.18 Inspection and Quality Assurance. Washers are hardened, compatible with Grade 8 systems. Nuts are Grade N8, compatible with Grade 8. Nylon resistant for up to 250 degrees F.

Precision-Matched Components: All fasteners are 1/2"-13 UNC for reliable fit and consistent clamping force across every assembly — no mismatched hardware, no guesswork. Black finish on bolts and nuts, yellow zinc on washers.

Built for Pros & Serious DIYers: Whether you’re repairing equipment, building fixtures, or assembling heavy components, this kit delivers industrial-grade reliability in a compact, easy-to-store format.

These 1/2"-13 x 3-1/2" (3.5") long Grade 8 (G8) Carriage Bolts are engineered for applications where strength, reliability, and vibration resistance matter most. Black finish on bolts and nuts. Each pack includes 10 Grade 8 carriage bolts, 10 hardened yellow zinc washers, and 10 nylon lock nuts. Designed for use in automotive repairs, trailer builds, agricultural equipment, shop machinery, and structural assemblies, this product eliminates the need to source parts separately—saving time while ensuring proper fit and performance. Whether you’re a professional mechanic, fabricator, or serious DIYer, this fastener kit delivers the confidence of industrial-grade hardware in a convenient, ready-to-use package.

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Product Details

SKU:: awhd-us-b0h8x1ycf7
Model:: QFG37291-FBA
Country:: US
ASIN:: B0H8X1YCF7

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Common questions about buying open-box and refurbished.

Why buy refurbished or open-box?

Refurbished and open-box products offer the same performance as new at a fraction of the price. You're already saving $3 on this listing. They've been inspected, tested, and are ready to use — the only difference is the price tag. Buying refurbished also reduces electronic waste, extending product life cycles and keeping functional devices out of landfills.

What's the difference between open-box and refurbished?

Open-box products are customer returns that have been inspected and confirmed functional. They may show little to no use — often the item was returned simply because the buyer changed their mind. Refurbished products have been professionally repaired or restored by technicians, tested to meet or exceed manufacturer specifications, and sometimes come with a warranty. Both are a smart alternative to buying new.

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