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HILLMAN 5/16 in. X 7 in. L Zinc-Plated Steel Carriage Bolt

Meet a dependable fastener designed for wood-first projects: the HILLMAN 5/16 in. x 7 in. L Zinc-Plated Steel Carriage Bolt. Built for durability and ease, this bolt combines a cla…

Hillman MPN 240132 In Stock & Ready to Ship
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About Product Overview

Meet a dependable fastener designed for wood-first projects: the HILLMAN 5/16 in. x 7 in. L Zinc-Plated Steel Carriage Bolt. Built for durability and ease, this bolt combines a classic carriage bolt design with a protective zinc finish to stand up to outdoor conditions and everyday use.

What makes this carriage bolt stand out is its thoughtful combination of size, finish, and construction. With a 5/16 in. diameter and 7 in. length, it’s a versatile option for common wood thicknesses and frame assemblies. The zinc-plated finish provides corrosion resistance for decks, fences, furniture frames, and other exterior woodworking projects. Made from Grade 2 steel, it offers reliable strength for standard carpentry tasks without adding unnecessary heft.

  • Size and material: 5/16 in. diameter, 7 in. length, steel construction (Grade 2).
  • Coarse thread: Optimized for fast, secure bites into softwoods and many common lumber species.
  • Finish: Zinc-plated for rust resistance in indoor and outdoor environments.
  • Head design: Carriage bolt with a domed head and a square under-head shoulder to resist turning as you tighten with a nut.
  • Packaging: Boxed, 1 piece per package.
  • Application type: Ideal for wood-to-wood connections in decks, fences, furniture frames, and other timber assemblies.

Why choose a carriage bolt for your project?

Carriage bolts differ from other fasteners because the square shoulder beneath the head bites into the wood, helping to prevent rotation during assembly. The smooth, rounded head provides a clean, unobtrusive finish on visible surfaces, while the coarse threads deliver strong, reliable engagement in softwood and many standard lumber species. This combination makes them especially well-suited for:

  • Deck and railing frameworks where a flush-looking head is preferred and you want steady, no-slip performance.
  • Outdoor furniture frames and garden structures that benefit from corrosion resistance without sacrificing strength.
  • Fencing components and timber-to-timber joints where quick installation with a reliable hold is important.

Install tips and best practices

For the best results, pair this carriage bolt with a matching hex nut and washer as needed. Use a drill to create a shank hole through the piece receiving the bolt, allowing the bolt to pass through cleanly before threading on the nut on the opposite side. Tighten carefully to draw the pieces together without over-stressing the wood. Remember, the square under the head helps keep the bolt from turning as you tighten, so you can secure your joint with confidence.

Whether you’re replacing aging hardware on an outdoor project or building a sturdy timber frame from scratch, this Hillman carriage bolt delivers straightforward strength, reliable corrosion resistance, and a finish designed to withstand the elements—making it a practical choice for DIYers, woodworkers, and professional installers alike.

The Details Specifications

Brand Hillman
SKU 57174
UPC 008236086843
Unit 0
Case Pack Quantity 4 per case
Retail Unit Quantity 1
Unit of Measure 50 BX
Dimensions (L × W × H) 5 × 9 × 4
Weight 7 lbs
Cubic Feet 0.15764 ft³
Country of Origin CHINA
Safety Data Sheet (SDS) Manufacturer documentation · opens in new tab

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