Simpson Strong-Drive SDCF TIMBER-CF Screw - 0.315 in. x 5 1/2 in. T40, E-Coat by Simpson Strong-Tie is a high-performance structural fastener engineered for cross-laminated timber (CLT), mass timber construction, and general interior wood-to-wood applications. The redesigned SDCF Timber-CF screw delivers uncompromised strength in demanding heavy timber, glulam, and engineered wood assemblies, combining a flat head with underhead nibs for a clean, flush countersink with a SawTooth point that starts fast and drives with reduced torque - no predrilling required in most applications. The black e-coat electrocoating finish adds a construction-durable, nonmetallic layer that resists corrosion in interior dry-service environments while also contributing to the screw's optimized hardness profile, helping mitigate the risk of brittle fracture for reliable, long-term performance.

Key Features

• Flat head with underhead nibs - enables clean countersinking into timber and engineered wood surfaces, leaving a flush, professional finish without additional prep work
• Heavy-duty, fully-threaded shank - maximizes thread engagement along the entire shank length, delivering superb withdrawal resistance in mass timber and multi-ply engineered wood applications
• SawTooth point - cuts into wood fibers quickly for fast starts and easy driving, reducing installation torque and eliminating the need for predrilling in most applications
• Black e-coat electrocoating finish - provides a construction-durable nonmetallic coating that resists corrosion in interior dry-service applications while enhancing aesthetics in exposed timber assemblies
• Deep T40 6-lobe recess - creates a secure, high-torque connection between driver and screw head, reducing cam-out and improving drive control during heavy timber installation
• Optimized hardness profile - works in combination with the e-coat finish to mitigate the risk of brittle fracture, supporting long-term structural integrity
• Compliant with CSA O86:24 hydrogen embrittlement requirements - meets current Canadian structural wood design standards, supporting use in code-compliant mass timber projects
• 0.315 in. diameter x 5 1/2 in. length - sized for deep penetration and strong purchase in thick timber members, beams, and multi-ply panels

Why This Product

• Purpose-built for mass timber and CLT construction - the SDCF Timber-CF screw is specifically designed for cross-laminated timber, glulam, heavy timber framing, and engineered wood multi-ply fastening, making it a purpose-matched choice where standard screws fall short
• Eliminates predrilling in most applications - the SawTooth point self-starts and reduces installation torque, saving significant time and labor on large timber assemblies where drilling every pilot hole would slow production
• Designed to resist brittle fracture risk - the combination of optimized hardness profile and e-coat electrocoating directly addresses a critical failure mode in structural screws, supporting reliable long-term performance in demanding load-bearing applications
• Compatible with Simpson Strong-Tie connectors - the SDCF screw is listed for use with Simpson Strong-Tie hardware connectors, allowing consistent, engineered fastening solutions across timber connections and beam reinforcement details

Specifications

• Brand: Simpson Strong-Tie
• Product Name: Strong-Drive SDCF TIMBER-CF Screw
• Length: 5 1/2 in.
• Shank Diameter: 0.230 in.
• Head Diameter: 0.590 in.
• Thread Length: 5 1/8 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