Simpson Strong-Drive SDHR COMBO-HEAD Screw - 12 mm x 100 mm, Black E-Coat by Simpson Strong-Tie is a heavy-duty structural fastener engineered for cross-laminated timber (CLT), mass timber construction, and general interior wood applications. With a robust combination head that accepts either a T40 6-lobe driver bit or a 17 mm hex-head driver bit, this partially-threaded screw delivers reliable connection strength when joining steel plate or angle connectors to wood. The black e-coat electrocoating finish offers corrosion resistance in interior dry-service environments, making this screw a dependable choice for engineered wood connections, factory-built construction, and steel-to-wood structural assemblies.

Key Features

• Black e-coat electrocoating finish - provides a construction-durable, nonmetallic, and friction-reducing coating for corrosion resistance in interior dry-service conditions, helping connections last in demanding structural environments
• Optimized hardness profile - helps mitigate field embrittlement issues and is compliant with CSA O86:24 hydrogen embrittlement requirements, giving builders confidence in structural performance and code compliance
• Combination head design (T40 6-lobe or 17 mm hex-head) - allows flexibility on the jobsite by letting installers drive with the bit they have on hand, reducing downtime and tool changes
• Hex head with deep T40, 6-lobe recess - provides a secure, slip-resistant drive that reduces cam-out and keeps the fastener under control during installation
• Type-17 point - ensures fast starts, reduces installation torque, and eliminates the need for predrilling in most applications, speeding up assembly in CLT and mass timber projects
• Heavy-duty shank with robust knurl - reduces installation torque during driving, lowering strain on the tool and the installer over long fastening sessions
• Designed for use with steel side plates - makes this screw an ideal choice for steel plate or angle connector attachments to engineered wood members
• Length: 100 mm (4 in.) with a 2 1/8 in. thread length - the partial thread profile is optimized for structural pull-through and withdrawal resistance in mass timber applications
• Shank diameter of 0.315 in. with a 0.669 in. head diameter - sized for structural-grade load transfer in heavy-duty wood and steel-to-wood connections

Why This Product

• Built for mass timber and CLT construction - specifically engineered for cross-laminated timber and mass timber structural connections where standard wood screws are not rated, making it the right tool for modern engineered wood assemblies
• No predrilling required in most applications - the Type-17 point and knurled shank allow the screw to self-drill into wood, saving time on large-scale structural framing projects without sacrificing connection integrity
• Dual driver compatibility removes guesswork - the combination head works with a 17 mm hex-head driver or a T40 6-lobe driver bit, so crews are not locked into a single tool type on the jobsite
• CSA O86:24 compliant hardness profile - the optimized heat treatment addresses hydrogen embrittlement concerns that can affect high-strength fasteners in the field, providing a verifiable level of quality assurance for code-sensitive structural projects

Specifications

• Brand: Simpson Strong-Tie
• Product Name: Strong-Drive SDHR COMBO-HEAD Screw
• Length: 100 mm (4 in.)
• Shank Diameter: 0.315 in.
• Head Diameter: 0.669 in.
• Thread Length: 2 1/8 in.
• Head Type: Combination
• Drive Type: T40 6-Lobe or Hex-Head
• Point Type: Type-17 Point
• Coating: E-coat Electrocoating
• Finish: E-coat Electrocoating
• Color: Black