IMSCREWS 3/8"-16 x 4-1/2" Heavy-Duty 304 Stainless Steel Carriage Bolts (10 PCS)

Substantial Strength for Thick Structural and Marine Construction
The IMSCREWS 3/8" x 4-1/2" carriage bolt is engineered for structural projects requiring deep penetration through thick materials. With a robust 3/8-inch diameter and an extended 4.5-inch length, these bolts are the ideal choice for securing standard 4x4 timber posts (actual 3.5" thickness) to additional structural beams or metal connectors. This length provides enough clearance to cross the post and a 1-inch board while leaving sufficient thread for heavy-duty washers and nuts to ensure a snug, permanent connection. Built for longevity, they offer the structural stability required for outdoor pergolas, heavy-duty fencing, and residential deck framing.

Superior Durability and Safety-Focused Design
Forged from premium 18-8 (304) stainless steel, these fasteners offer superior resistance to rust and corrosion, even when exposed to harsh coastal or humid environments. The smooth round head creates a clean, tamper-resistant look that reduces snagging hazards, making them a safe choice for high-traffic areas like playground equipment, boardwalks, and residential decks. The integrated square neck prevents the bolt from spinning during installation, allowing for easy, one-sided fastening with a single wrench from the nut side.

Specifications:
Thread Size: 3/8"-16 Coarse (UNC); Length: 4-1/2" (Measured from Under Head); Material: 304 (18-8) Stainless Steel; Full Thread

Pro-Tips:
1. Use a 3/8" drill bit to ensure a snug, structural fit for the square neck.
2. Pair with 304 SS flat washers and hex nuts to distribute heavy structural loads and protect wood fibers.

Key Features

• Extended 4.5 Reach: Designed for deep penetration through standard 4x4 posts (3.5 actual) with additional space for heavy-duty brackets or double lumber.
• Structural 3/8 Shank: The 3/8-inch diameter provides high shear resistance for load-bearing joints in deck framing and outdoor timber structures.
• Corrosion-Resistant 304 SS: Forged from 18-8 (304) stainless steel, offering high durability in humid environments and with treated lumber.
• Smooth Safety Head: The rounded, drive-free head minimizes snagging hazards, providing a clean finish for benches, railings, and play sets.
• Self-Locking Square Neck: The precision square shoulder bites into wood to prevent spinning, enabling efficient one-sided installation from the nut side.

Specifications

• ASIN: B0F2F6VQF6
• Internal SKU: IMS0866
• Size: 3/8"-16 x 4-1/2"
• Material: Stainless Steel
• Finish: Stainless Steel
• Head Style: Round
• Package Quantity: 10