Simpson Strong-Drive SDCF TIMBER-CF Screw - 0.315 in. x 8-5/8 in. T40, E-Coat by Simpson Strong-Tie is a heavy-duty structural fastener engineered for cross-laminated timber (CLT), mass timber construction, and demanding general interior wood applications. Redesigned for performance, this fully-threaded timber screw delivers uncompromised withdrawal resistance and reliable long-term strength in engineered wood, glulam, heavy timber framing, and multi-ply fastening situations. The black e-coat electrocoating finish gives it a clean, professional appearance while providing construction-durable corrosion resistance for interior dry-service environments - making it a go-to choice for structural wood-to-wood, wood-to-steel, and connector fastening work.

Key Features

• Flat head with underhead nibs - enables clean, flush countersinking so the screw sits level with the wood surface for a professional finish in visible timber applications
• Heavy-duty, fully-threaded shank (0.230 in. shank diameter) - maximizes grip and withdrawal resistance along the full 8 5/8 in. length, delivering the structural holding power required for mass timber and CLT connections
• SawTooth point - provides fast starts and reduced installation torque, eliminating the need for predrilling in most applications and significantly speeding up high-volume timber fastening work
• Black e-coat electrocoating finish - a construction-durable nonmetallic coating that resists corrosion in interior dry-service conditions while enhancing the aesthetics of exposed timber connections
• Optimized hardness profile - works alongside the e-coat finish to mitigate the risk of brittle fracture, supporting reliable, long-term structural performance in demanding load applications
• Deep T40 6-lobe recess drive - provides a secure, cam-out-resistant connection between driver and fastener, reducing slippage and driver wear during high-torque installation into heavy timber
• Compliant with CSA O86:24 hydrogen embrittlement requirements - meets Canadian standard requirements, supporting use in code-compliant mass timber and CLT structural assemblies
• Thread length: 8 1/4 in. - near full-length threading ensures engagement throughout the fastener's depth for maximum wood-to-wood clamping and pull-through resistance

Why This Product

• Purpose-built for mass timber and CLT construction - unlike general-purpose wood screws, this fastener is specifically designed for cross-laminated timber and engineered wood applications where structural integrity and precise countersinking are critical requirements
• Eliminates predrilling in most applications - the SawTooth point cuts into wood fibers cleanly on entry, reducing labor time and setup steps on job sites where hundreds of fasteners may be driven into heavy timber members
• Includes a T40 6-lobe driver bit in the package - the required driver bit is included, so installers can get to work immediately without sourcing a separate bit for this specialized drive format
• Meets CSA O86:24 hydrogen embrittlement requirements - for projects requiring compliance with Canadian engineered wood standards, this screw satisfies the hydrogen embrittlement specification, reducing risk and supporting code approval documentation

Specifications

• Brand: Simpson Strong-Tie
• Product Name: Strong-Drive SDCF TIMBER-CF Screw
• Length: 8 5/8 in.
• Shank Diameter: 0.230 in.
• Head Diameter: 0.590 in.
• Thread Length: 8 1/4 in.
• Head Type: Flat Head with Nibs
• Drive Type: T40 6-Lobe
• Point Type: SawTooth Point
• Coating: E-coat Electrocoating
• Finish: E-coat Electrocoating
• Color: Black