Mutual Screw & Supply

5/16-18 X 4-1/2" Carriage Bolts | Fully Threaded | A307 Grade A Plain Steel (325 / Pkg.)

5/16-18 X 4-1/2" Carriage Bolts | Fully Threaded | A307 Grade A Plain Steel - Main image
$53.35 $84.68 In stock

5/16-18 X 4-1/2" 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: 4-1/2"
  • Threads Per Inch: 18
  • Material: A307 Grade A Plain Steel
  • Finish: Plain
  • Thread Style: Fully Threaded
  • Pack Quantity: 325
Before you pay

Check the method and total at checkout.

When it ships

Allow for processing time as well as the journey to you.

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

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

View policy
If you need a refund

Keep your order number and contact the store to start.

Please contact us for the refund processing timeframe before returning an item.

View policy
Delivery costs

Review the cost for your destination and chosen service.

Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

View policy
Returning an item

Check the return conditions before sending anything back.

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

View policy

Customer Reviews (4.8 / 5 · 5 reviews)

Ellie N. ★★★★★

These bolts worked perfectly for building a heavy-duty workbench, and the fully threaded shafts gave me a solid grip through multiple layers of wood. A full box of 325 means I’ve got plenty left over for future projects, which is a nice bonus.

Charlotte T. ★★★★★

The square neck on these carriage bolts really bites into the wood, so they don't spin when you're tightening them. They're a solid choice for anything that needs a secure, heavy-duty connection.

Evelyn ★★★★★

Fifty pounds of these showed up and the threading is clean all the way to the end, which makes a difference when you're stacking washers and nuts. The square neck seats solidly into the wood on my fence repairs, so I didn't have to hold a wrench on the head once. Solid value for the bulk price.