Mutual Screw & Supply

5/16-18 X 3-1/2" Carriage Bolts | Fully Threaded | A307 Grade A Plain Steel (100 / Pkg.)

5/16-18 X 3-1/2" Carriage Bolts | Fully Threaded | A307 Grade A Plain Steel - Main image
$14.4 $21.18 In stock

5/16-18 X 3-1/2" Carriage Bolts in A307 Grade A Plain Steel. Carriage bolts feature a smooth, rounded head with a square neck underneath that pulls into the material to prevent the bolt from turning during installation, making them ideal for wood-to-wood and wood-to-metal connections.

  • Domed head with square anti-rotation neck
  • A307 Grade A Plain Steel construction
  • Coarse thread for use in wood and with nuts and washers
  • Fully Threaded
  • Sold in bulk packs

Specifications

  • Thread Size: 5/16-18
  • Length: 3-1/2"
  • Threads Per Inch: 18
  • Material: A307 Grade A Plain Steel
  • Finish: Plain
  • Thread Style: Fully Threaded
  • Pack Quantity: 50
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Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

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United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.

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Customer Reviews (5.0 / 5 · 5 reviews)

Carter ★★★★★

The square neck grabbed tight into the wood just as described, no spinning at all when I tightened them. For a 3.5-inch bolt they feel solid enough for heavy furniture assembly.

Kevin S. ★★★★★

These are exactly the right length for joining my planter boxes together, and the fully threaded shaft gave me plenty of grip when I tightened them. The square neck locked into the wood just like it should, so no spinning or cursing on this project.

Michael X. ★★★★★

The square neck under the head bit right into the wood on my deck repairs and held firm while I torqued them down. All 100 bolts came threaded clean with no burs, and the 3-1/2 inch length is perfect for sandwiching two 2x4s. Finished my project in under an hour without a single stripped thread.