Simpson Strong-Drive SDWH TIMBER-HEX Stainless Steel Screw - 0.185" x 4-1/2" is a structural hex-head fastener engineered as a direct replacement for traditional lag screws in wood-framing applications. Built from Type 316 stainless steel, this screw delivers maximum corrosion resistance suitable for demanding outdoor environments, coastal exposure, and contact with treated lumber. The hex washer head and sharp point design allow for fast, drill-free installation, saving time on the job while meeting 2018 and 2021 IRC and IBC code requirements for common structural wood-framing tasks.

Key Features

• Type 316 Stainless Steel material and finish - provides superior resistance to corrosion, rust, and chemical exposure, making this screw ideal for wet, coastal, and pressure-treated lumber applications where standard fasteners would degrade over time.
• No predrilling required in most applications - the sharp point and box thread design allow the fastener to drive directly into wood, reducing installation time and eliminating the need for a separate drill step compared to typical lag screws.
• 5/16 in. hex drive with hex washer head - the large-bearing hex washer head distributes clamping force evenly across the surface, reducing the chance of surface crushing and providing a secure, professional-grade connection.
• Box thread design with raised-ridge technology - significantly reduces driving torque during installation, reducing installer fatigue and making it practical to drive multiple fasteners quickly without stripping or over-driving.
• Sharp point tip - allows the screw to self-start in wood without wandering, improving placement accuracy and speeding up repetitive structural fastening tasks.
• 2 3/4 in. thread length on a 4-1/2 in. shank - provides deep thread engagement in the receiving member for strong, code-compliant connections in structural framing assemblies.
• Meets 2018 and 2021 IRC and IBC code requirements - enables use in inspected and permitted construction projects for several common wood-framing applications without the uncertainty of substitution approvals.
• Driver bit included - the fastener ships with a 5/16 in. hex driver bit so installers can begin work immediately without sourcing a separate accessory.

Why This Product

• Eliminates predrilling in most wood-framing scenarios - unlike traditional lag screws that require a pilot hole, this fastener's sharp point and box thread profile let it drive directly into framing lumber, cutting installation steps and labor time on structural jobs.
• Type 316 stainless steel stands up where standard fasteners fail - whether used in deck ledger connections, outdoor structural assemblies, or environments with high moisture or chemical exposure, the 316 SS construction resists the corrosion that causes standard zinc-coated lag screws to weaken or seize over time.
• Code-listed for 2018 and 2021 IRC and IBC applications - contractors and inspectors working on permitted residential and commercial wood-framing projects can rely on this fastener to satisfy structural requirements without substitution paperwork or engineering sign-off for listed applications.
• Designed as a direct lag-screw replacement - the 0.185 in. shank diameter, hex washer head, and structural thread geometry make this a purpose-built swap for lag screws in common connections, so existing plans and load tables for lag applications can reference this fastener directly.

Specifications

• Brand: Simpson Strong-Tie
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Shank Diameter (in.): 0.185
• Length (in.): 4 1/2
• Head Type: Hex Washer Head
• Head Diameter (in.): 0.455
• Drive Type: 5/16 in. Hex
• Thread Type: Box Threads
• Thread Length (in.): 2 3/4
• Point Type: Sharp Point
• Country of Origin: Taiwan

Available Pack Options

• SDWH19450SS-R10: 10 Pk - includes (1) driver bit
• SDWH19450SS-R100: 100 Pk - includes (1) driver bit

Frequently Asked Questions

Does this screw require a pilot hole before installation?

No. The sharp point and box thread design allow this fastener to be driven directly into wood without predrilling in most applications, making installation faster and simpler than working with traditional lag screws.

What building codes does this fastener comply with?

This screw meets 2018 and 2021 IRC (International Residential Code) and IBC (International Building Code) requirements for several common wood-framing applications, making it suitable for permitted residential and commercial construction projects.

Why is Type 316 stainless steel used for this fastener instead of a standard coating?

Type 316 stainless steel is the material of both the screw's body and finish, offering a higher level of corrosion resistance than typical zinc or galvanized coatings. This makes it well suited for outdoor structural connections, coastal environments, and applications involving pressure-treated lumber where moisture and chemical exposure are concerns.

What tool is needed to drive this screw?

This fastener uses a 5/16 in. hex drive and is installed with a hex driver. A driver bit is included with the product so you can begin installation right away without sourcing a separate accessory.

Note: Product dimensions and/or thread length may differ from picture.