Simpson Strong-Drive DWP Wood SS #12 x 4" Flat Head Screw in Type 316 Stainless Steel is a load-rated structural fastener engineered for demanding exterior applications where corrosion resistance and verified performance are non-negotiable. Designed for docks, boardwalks, decks near water, and other environments exposed to high or severe corrosion, this screw delivers the holding power and material integrity needed for long-lasting structural connections. The T27 6-Lobe drive, sharp point, and proprietary box-thread geometry make it a reliable choice for fastening wood, engineered wood, and polymer materials in the harshest outdoor conditions.

Key Features

• Type 316 Stainless Steel material - provides superior resistance to saltwater, moisture, and aggressive corrosion in seaside and waterfront environments where standard fasteners would degrade prematurely.
• Unique box-thread design with raised-ridge technology - greatly reduces driving torque so you can drive more screws on a single battery charge, saving time and battery life on large decking or dock projects.
• Specially designed sharp point - penetrates hardwood and dense wood products with ease, eliminating the need for pre-drilling in many applications and speeding up installation.
• T27 6-Lobe drive - provides a secure bit fit that reduces cam-out, resulting in a smooth, consistent drive and extended bit life even during high-volume fastening work.
• Flat head profile with 0.435" head diameter - sits flush with the surface for a clean, finished appearance on deck boards, dock planks, and exterior structural members.
• ICC-ES AC233 tested and load-rated - these structural fasteners are rated for shear, pull-through, and withdrawal resistance, so you have documented performance data to meet code requirements and inspection standards.
• 4-inch length with #12 screw size - offers the depth of engagement needed for solid, long-term structural connections in thick decking assemblies and dimensional lumber.

Why This Product

• Built for high-corrosion environments: Type 316 stainless steel offers a higher level of corrosion protection than 304 stainless, making it the correct choice for docks, boardwalks, and coastal decks that face constant exposure to saltwater and humidity.
• Structural confidence backed by testing: Because these screws are tested under ICC-ES acceptance criteria AC233 and carry load ratings for shear, pull-through, and withdrawal, they support code-compliant structural connections - not just general fastening.
• Reduced installer fatigue and faster job completion: The box-thread design's reduced driving torque means less strain on your tool and your wrist during extended fastening sessions on large dock or deck installations.
• Versatile across exterior structural materials: Rated for use with wood, engineered wood, and polymer materials, this screw adapts to a wide range of exterior structural connection scenarios without requiring a different fastener for each substrate.

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #12
• Length: 4 in.
• Head Type: Flat Head
• Head Diameter: 0.435 in.
• Drive Type: T27 6-Lobe
• Thread Type: Box Threads
• Point Type: Sharp Point
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Approx. Count Per Lb: 36
• Country of Origin: Taiwan

Available Pack Options

• T12400WP1: 1 Lb (36) - includes (1) T27 6-lobe driver bit
• T12400WP5: 5 Lb (180) - includes (1) T27 6-lobe driver bit
• T12400WPB: 750 Pk - includes (2) T27 6-lobe driver bits

Approved Applications

• Deck construction and deck board fastening
• Dock and pier structural connections
• Boardwalk framing and decking
• General exterior structural applications near water
• Environments with high or severe corrosion exposure
• Connections using wood, engineered wood, and polymer materials

Frequently Asked Questions

What makes Type 316 stainless steel the right choice for waterfront applications?

Type 316 stainless steel provides a higher level of corrosion resistance compared to standard stainless grades, making it specifically suited for docks, boardwalks, and coastal decks that are exposed to saltwater, moisture, and chemically aggressive environments. Simpson designates this material as the recommended choice for seaside applications where long-term fastener integrity is critical.

Are these screws rated for structural use, or are they general-purpose fasteners?

These are structural fasteners. They have been tested in accordance with ICC-ES acceptance criteria AC233 and carry load ratings for shear, pull-through, and withdrawal resistance. This testing and rating makes them appropriate for code-compliant exterior structural connections rather than general fastening tasks.

What drive bit is required for the Strong-Drive DWP Wood SS screw?

These screws use a T27 6-Lobe drive, which requires a T27 Torx-compatible bit. The 6-lobe geometry provides a secure bit-to-fastener fit that minimizes cam-out during driving, extending bit life and improving drive consistency.

Can the sharp point penetrate hardwood without pre-drilling?

The DWP Wood SS features a specially designed sharp point intended to penetrate hard wood products with ease. Simpson's design is aimed at reducing or eliminating the need for pre-drilling in many hardwood and engineered wood applications, though project-specific material density and thickness should always be evaluated before installation.