IMSCREWS 5/16"-18 x 4" Heavy-Duty 304 Stainless Steel Carriage Bolts (5 Pack)

Substantial Support for Thick Structural Connections
The IMSCREWS 5/16" x 4" carriage bolt is engineered for projects requiring deep penetration and reliable structural support. With a robust 5/16-inch diameter and an extended 4-inch length, these bolts are well-suited for high-load joints where stability is critical, such as through-bolting standard 4x4 posts or reinforcing heavy-duty deck-to-post connections. Built for durability, they offer the stability necessary for long-term use in outdoor structures, garden gazebos, and residential DIY projects.

High Durability and Safety-Focused Design
Forged from premium 18-8 (304) stainless steel, these fasteners are highly resistant to rust and corrosion in coastal or humid environments. The smooth round head offers a clean appearance that reduces snagging hazards, making them an ideal choice for railings, play sets, and benches. The integrated square neck prevents rotation, allowing for easy, one-sided installation with a single wrench from the nut side.

Specifications:
- Thread: 5/16"-18 Coarse (UNC); Length: 4" (Measured from Under Head)
- Material: 304 (18-8) Stainless Steel; Full Thread

Pro-Tips:
1. Use a 5/16" drill bit to ensure a snug, structural fit for the square neck.
2. Pair with stainless steel flat washers on the nut side to distribute structural load and protect wood fibers.

Key Features

• Self-Locking Square Neck: Features a precision-engineered square neck beneath the head that bites into wood, preventing the bolt from spinning while the nut is tightened for easy, one-sided installation.
• Full Thread Maximum Grip: The fully threaded 4-inch shank provides maximum grip and enhanced fastening power along its entire length, making it ideal for extra-deep timber and structural projects.
• 304 Marine Grade Stainless: Forged from premium 18-8 (304) Stainless Steel for superior corrosion defense. Essential for docks, coastal decks, and ACQ pressure-treated lumber.
• Extended Structural Strength: The 5/16 diameter delivers professional-grade shear resistance. At 4 long, these bolts are Well-suited for through-bolting thick posts and heavy structural timber framing.
• Snag-Free Aesthetic Finish: The smooth, domed round head provides a professional finish without sharp edges, ensuring safety for playground equipment, fencing, and furniture.

Specifications

• ASIN: B0F2F47LP7
• Internal SKU: IMS0817
• Size: 5/16"-18 x 4"
• Material: Stainless Steel
• Finish: Stainless Steel
• Head Style: Round
• Package Quantity: 5