Simpson Strong-Drive SDHR COMBO-HEAD Screw - 10 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 dry-service applications. The unique combination hex head accepts either a 15 mm hex-head driver bit or a T40 6-lobe driver bit, giving installers flexibility on the job site without sacrificing drive security. Built with a robust knurled shank, a Type-17 self-drilling point, and a black e-coat electrocoated finish, this screw is purpose-built to connect steel plate and angle connectors to wood with exceptional holding strength - no predrilling required in most applications.

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 fasteners perform reliably over the long term
• Optimized hardness profile - helps mitigate field embrittlement issues and is compliant with CSA O86:24 hydrogen embrittlement requirements, reducing the risk of fastener failure in structural applications
• Combination head design (T40 6-lobe or 15 mm hex-head driver bit compatibility) - gives installers the flexibility to use the bit already on hand, saving time during structural assembly
• Heavy-duty shank with robust knurl - reduces installation torque so screws drive faster and with less strain on tools and operators
• Type-17 point - ensures fast starts, lowers installation torque, and eliminates the need for predrilling in most applications, speeding up structural timber work
• Partially threaded design with 2 1/8 in. thread length - concentrates clamping force where it is needed most, making this screw especially effective when connecting steel side plates to wood or engineered lumber
• Hex head with deep T40, 6-lobe recess - delivers a secure, cam-out-resistant drive even under high torque, reducing stripped-head failures in the field
• Head diameter of 0.590 in. and shank diameter of 0.275 in. - dimensioned for structural-grade load transfer in mass timber and CLT connections
• Designed for use with steel side plates - making it a go-to fastener for steel-to-wood and steel-to-engineered-wood connections in timber frame construction

Why This Product

• Engineered specifically for mass timber and CLT construction - the SDHR Combo-Head screw is one of the few structural hand-drive fasteners purpose-designed for cross-laminated timber and factory-built or modular wood construction, where connection strength and consistent installation torque are critical.
• Dual drive compatibility saves time on complex job sites - the combination hex and T40 6-lobe head means crews are not forced to stop and swap bits, keeping installation moving efficiently whether using a hex or 6-lobe driver.
• Self-drilling Type-17 point eliminates extra prep steps - in most applications there is no need for predrilling, which reduces labor time and the number of tools needed when fastening into engineered wood, CLT panels, or solid timber members.
• CSA O86:24 compliant hardness profile addresses a real field concern - the optimized hardness helps mitigate embrittlement issues that can compromise structural integrity over time, providing added confidence in long-term performance for dry-service interior applications.

Specifications

• Brand: Simpson Strong-Tie
• Length: 4 in. (100 mm)
• Shank Diameter: 0.275 in.
• Head Diameter: 0.590 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