The Simpson Strong-Drive SDCP Timber-CP Screw with T40 6-Lobe drive and Yellow-Zinc coating is a structural fastener engineered for cross-laminated timber (CLT) construction, mass timber framing, and general interior structural applications. Designed to pull heavy structural members together with superb holding power, this partially-threaded screw features a flat head with underhead nibs for clean, flush countersinking into wood surfaces. The yellow-zinc finish provides a protective coating suited for interior structural use, making this screw a reliable choice for demanding timber connections where precision and strength matter.

Key Features

• Yellow-Zinc Coating - provides a protective finish that helps guard the fastener against corrosion during storage and interior use, extending service life in structural applications
• 11-Inch Length - offers deep penetration into structural members, creating strong and durable connections in thick timber assemblies including CLT panels and mass timber construction
• T40 6-Lobe Drive Type - delivers high torque transfer with reduced cam-out compared to conventional drives, allowing for more controlled and efficient installation in dense timber
• Flat Head with Underhead Nibs - the nibs bite into the wood surface to prevent the head from spinning during installation, enabling clean, flush countersinking without surface damage
• Type-17 Point - self-drilling point design pierces wood fibers cleanly, reducing the need for pre-drilling in many applications and speeding up installation
• Partial Thread Design (3-1/8 in. thread length) - the unthreaded shank allows the screw to clamp structural members tightly together, pulling them into firm contact for rigid, secure connections
• 0.275 in. Shank Diameter - heavy-duty shank provides exceptional shear and withdrawal strength, making this screw appropriate for high-load structural framing connections
• 0.7 in. Head Diameter - wide flat head distributes clamping load across a larger bearing area, reducing the risk of the head pulling through engineered wood panels

Why This Product

• Engineered specifically for cross-laminated timber and mass timber construction, this screw addresses the unique demands of CLT panel connections, surface splines, and lap joints where standard fasteners may lack the necessary holding power or head geometry.
• The partially-threaded design is the right choice when pulling structural members tightly together is critical - the unthreaded shank acts as a clamp, eliminating gaps between mating surfaces that fully-threaded screws can leave behind.
• The T40 6-Lobe drive reduces installer fatigue and tool wear during high-volume structural framing work, as the geometry maintains a secure bit-to-screw engagement even under high torque in dense wood species.
• With applications ranging from wall-to-wall and floor-to-floor connections to panel-to-beam and ledger connections, this versatile structural screw consolidates fastener inventory for general timber framing projects.

Specifications

• Brand: Simpson Strong-Tie
• Finish: Yellow-Zinc Coated
• Length: 11 in.
• Head Diameter: 0.7 in.
• Shank Diameter: 0.275 in.
• Drive Type: T40 6-Lobe
• Head Type: Flat Head with Nibs
• Thread Length: 3-1/8 in.
• Point Type: Type-17 Point
• Measurement Unit: Pack

Available Pack Options

• SDCP271100-R30: 30 Pk
• SDCP271100: 150 Pk

Approved Applications

• Wall to wall connections
• Floor to floor connections
• Wall to floor connections
• Panel to beam connections
• Panel to wall connections
• Surface splines
• Lap joints
• Ledger connections
• General timber framing and interior structural applications
• Cross-laminated timber (CLT) construction
• Mass timber construction

Frequently Asked Questions

What type of construction is this screw designed for?

This screw is designed specifically for cross-laminated timber (CLT) construction, mass timber construction, and general interior structural applications. It is suitable for connections such as wall to wall, floor to floor, panel to beam, panel to wall, ledger connections, surface splines, and lap joints.

Why is a partially-threaded screw used for structural timber connections?

The partial thread design - with a 3-1/8 in. thread length on an 11 in. screw - means the unthreaded shank does not engage the first member being fastened. This allows the screw to draw the two structural members tightly together with clamping force, eliminating gaps at the joint for a rigid, high-strength connection.

Does the Type-17 point require pre-drilling?

The Type-17 point is a self-drilling point designed to pierce wood fibers cleanly, which reduces or eliminates the need for pre-drilling in many timber applications. For very dense or hard wood species, pre-drilling may still be recommended to prevent splitting - always consult applicable engineering guidelines for your specific application.

What bit size is required to drive this screw?

This screw uses a T40 6-Lobe drive, which requires a T40 Torx-compatible driver bit. The 6-lobe geometry provides high torque transfer and minimizes cam-out during installation, making it well-suited for driving into dense structural timber members.

Note: Product dimensions and/or thread length may differ from picture. Please see item description for specifications.