The Simpson Strong-Drive SDS Heavy-Duty Connector Screw in 1/4 in. diameter x 3-1/2 in. length is a high-strength structural fastener engineered by Simpson Strong-Tie for demanding connector installations, wood-to-wood assemblies, and engineered wood applications. Featuring a corrosion-resistant double-barrier coating and a no-predrill Type-17 point, this hex-head screw delivers reliable performance in structural framing, hardware attachment, and engineered lumber connections - making it a go-to choice for contractors and builders who need a strong, code-tested fastening solution.

Key Features

• Type-17 Point - enables easy, no-predrill installation, saving labor time and reducing the risk of wood splitting during driving
• 3/8 in. Hex Head - drives with a standard hex driver bit for fast, torque-efficient installation with a low-speed drill
• Double-Barrier Coating - provides corrosion resistance that protects fastener integrity in demanding structural environments and helps extend service life
• Serrated Threads at 10 TPI - grip wood fibers aggressively for a secure, high-strength hold in solid wood and engineered wood products
• 2-1/4 in. Thread Length on a 3-1/2 in. Shank - optimized thread-to-shank ratio delivers reliable pull-through and shear resistance in connector applications
• 0.235 in. Shank Diameter - sized for high structural load capacity while fitting standard connector hole patterns without predrilling
• Extensively Tested Design - validated across a wide range of connector and wood-to-wood applications, supporting confidence in structural performance

Why This Product

• No predrilling required - the Type-17 point drives cleanly into wood and engineered lumber, eliminating a full step from the installation process and keeping your workflow moving on framing and connector jobs
• Purpose-built for Simpson Strong-Tie connector installations - the screw geometry and shank diameter are engineered to align with connector hole patterns, ensuring tested structural performance when used with Simpson hardware
• The double-barrier coating delivers corrosion resistance that matters in structural applications where fastener degradation would compromise the integrity of the connected assembly over time
• Versatile enough for wood-to-wood and engineered wood applications - one screw type that performs across multiple structural fastening scenarios on the job site, reducing the need to carry multiple fastener types

Specifications

• Brand: Simpson Strong-Tie
• Length: 3-1/2 in.
• Shank Diameter: 0.235 in.
• Thread Length: 2-1/4 in.
• TPI: 10
• Thread Type: Serrated Threads
• Head Type: Hex Head
• Drive Type: 3/8 in. Hex
• Point Type: Type-17 Point
• Finish: Double-Barrier Coating
• Coating: Double-Barrier Coating

Available Pack Options

• SDS25312-R10: 10 Pk
• SDS25312-R25L: 25 Pk - includes (1) 3/8-in. hex-driver bit included
• SDS25312MB: 125 Pk
• SDS25312: 900 Pk

Approved Applications

• Fastening Simpson Strong-Tie Connectors
• Wood-to-wood structural connections
• Engineered wood product fastening

Install With

• A low-speed 1/2 in. drill with a 3/8 in. hex driver is the recommended tool for installation

Frequently Asked Questions

Does this screw require predrilling before installation?

No predrilling is required. The Type-17 point is specifically designed for easy driving directly into wood and engineered wood products without a pilot hole, which speeds up the installation process and simplifies connector attachment work.

What tool is recommended for driving this screw?

A low-speed 1/2 in. drill fitted with a 3/8 in. hex driver is the recommended installation tool, matching the 3/8 in. hex head design of this screw.

What is the coating on this screw and why does it matter?

This screw features a double-barrier coating, which provides corrosion resistance to help maintain fastener integrity in structural applications. The coating is applied to support the long-term durability of the connection in demanding conditions.

Can this screw be used with engineered wood products?

Yes. This screw is designed and tested for use in wood-to-wood connections as well as engineered wood applications, in addition to its primary use in fastening Simpson Strong-Tie connectors. The serrated threads and 10 TPI thread pattern help ensure a strong mechanical grip across these material types.

Note: The image displayed is a generic representation of the type of product. Product dimensions and/or thread length may differ from picture. Please see the item description above for specifications.