Simpson Strong-Drive DWP Wood Screw in #12 x 4" with Type 305 Stainless Steel Flat Head is a load-rated structural fastener engineered for deck, dock, boardwalk, and general exterior applications where corrosion resistance and verified load performance are non-negotiable. Built with a T27 6-Lobe drive and featuring a sharp point with unique box threads, this screw drives smoothly into wood, engineered wood, and polymer materials while delivering tested resistance to shear, pull-through, and withdrawal forces - making it a dependable choice wherever structural connections meet moisture, humidity, or corrosive outdoor environments.

Key Features

• Type 305 Stainless Steel material - delivers extra corrosion protection beyond standard coated fasteners, making this screw well-suited for high or severe corrosion environments such as docks, boardwalks, and decks near water.
• Flat head profile with 0.435 in. head diameter - sits flush against the surface for a clean, low-profile finish that won't snag or create trip hazards on deck and dock surfaces.
• Unique box thread design - greatly reduces driving torque compared to standard threads, so you can drive more screws per battery charge and reduce installer fatigue on large projects.
• Sharp point tip - penetrates hardwood and dense engineered 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-to-fastener fit that minimizes cam-out, resulting in easier driving and extended bit life over the course of a project.
• Tested to ICC-ES acceptance criteria AC233 - this screw carries verified load ratings for shear, pull-through, and withdrawal resistance, so you can use it with confidence in structural exterior connections where code compliance matters.
• 4 in. length in #12 diameter - provides substantial fastening depth for thick decking, framing members, and structural assemblies common in dock and deck construction.

Why This Product

• Verified structural performance for exterior connections - because these screws are load-rated in accordance with ICC-ES AC233 for shear, pull-through, and withdrawal, they are appropriate for structural deck, dock, and boardwalk connections where a standard wood screw is not sufficient.
• Extra corrosion protection where coatings fall short - Type 305 Stainless Steel construction resists the high or severe corrosion conditions found near water, making these screws a better long-term choice for marine-adjacent and waterfront applications than zinc-coated alternatives.
• Engineered for efficiency on large-scale exterior projects - the combination of box threads that reduce driving torque and a sharp point that penetrates dense wood means faster installation and less battery consumption, which matters on big deck or dock builds.
• Reliable drive system that protects your tools - the T27 6-Lobe drive reduces bit slippage and cam-out, protecting both the fastener head and your driver bits and keeping work moving without interruption.

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #12
• Length (in.): 4
• Head Type: Flat Head
• Head Diameter (in.): 0.435
• Drive Type: T27 6-Lobe
• Thread Type: Box Threads
• Point Type: Sharp Point
• Material: Type 305 Stainless Steel
• Finish: Type 305 Stainless Steel
• Approx. Count Per Lb: 36
• Country of Origin: Taiwan

Available Pack Options

• S12400WP1: 1 Lb (36) - includes (1) T27 6-lobe driver bit
• S12400WP5: 5 Lb (180) - includes (1) T27 6-lobe driver bit
• S12400WPB: 800 Pk - includes (2) T27 6-lobe driver bits

Frequently Asked Questions

What applications is the Simpson Strong-Drive DWP Wood Screw designed for?

The Strong-Drive DWP Wood SS screw is designed for deck, dock, and general exterior applications where extra corrosion protection and load specifications are required. It is particularly well suited for exterior structural connections such as docks, boardwalks, and decks near water or in environments with high or severe corrosion exposure.

Is this screw structurally rated, and what testing standard applies?

Yes. The Strong-Drive DWP Wood SS flat-head screw has been tested in accordance with ICC-ES acceptance criteria AC233 and is load rated for shear, pull-through, and withdrawal resistance, making it appropriate for structural exterior connections.

What is the advantage of the box thread design on this screw?

The unique box thread design greatly reduces driving torque compared to standard thread profiles. This allows installers to drive more screws on a single battery charge, improving efficiency on large deck or dock projects and reducing overall driver fatigue.

Is Type 305 Stainless Steel appropriate for seaside or saltwater applications?

Type 305 Stainless Steel provides strong corrosion resistance and is rated for high or severe corrosion environments. For seaside or direct saltwater exposure, Simpson recommends considering Type 316 stainless steel for that level of corrosive environment.

Note: Product dimensions may differ from picture.