Mutual Screw & Supply

5/16-18 X 8-1/2" Carriage Bolts | A307 Grade A Plain Steel (50 / Pkg.)

5/16-18 X 8-1/2" Carriage Bolts | A307 Grade A Plain Steel (50 / Pkg.) - Main image
$17.14 $25.2 In stock

5/16-18 X 8-1/2" 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
  • Sold in bulk packs

Specifications

  • Thread Size: 5/16-18
  • Length: 8-1/2"
  • Threads Per Inch: 18
  • Material: A307 Grade A Plain Steel
  • Finish: Plain
  • Pack Quantity: 25
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Standard Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

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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 (4.8 / 5 · 5 reviews)

Andrew ★★★★★

The square neck on these bolts grabbed perfectly into the wood on my trailer deck, no spinning at all while I tightened the nut. They’re a solid, no-frills choice for any heavy framing job.

Hannah B. ★★★★★

I’ve been using these for a heavy gate hinge repair, and the square neck grabs the wood perfectly without spinning. The rounded head looks clean and sits flush, though a few bolts had slight burrs that needed a quick file.

Ellie U. ★★★★★

Used these for a heavy-duty outdoor bench build and the 8-1/2" length was just right to go through thick pressure-treated lumber. The square neck locked into the wood perfectly, no spinning while tightening the nut.