The Simpson Strong-Drive SDCP Timber-CP Screw is a heavy-duty structural fastener engineered for cross-laminated timber construction, mass timber assemblies, and general interior framing applications. Featuring a 0.390 in. head profile, 12-1/2 in. overall length, and a T40 6-Lobe drive, this partially-threaded screw is built to pull structural members together with exceptional holding power - making it a trusted choice for demanding timber-to-timber connections where precision and strength are critical.

Key Features

• 0.390 in. Screw Diameter with 0.275 in. Shank - provides the structural cross-section needed to handle heavy timber loads without sacrificing installation ease
• 12-1/2 in. Length - reaches deep into thick timber members to create solid, load-rated connections across a wide range of mass timber assemblies
• Flat Head with Underhead Nibs (0.7 in. Head Diameter) - the nibs bite into the wood surface as the screw seats, delivering clean, flush countersinking without the need for pre-drilling a countersink
• T40 6-Lobe Drive - transfers high torque with minimal cam-out, giving installers better control and reducing bit wear on the job site
• Partial Thread Design with 3-1/8 in. Thread Length - the unthreaded shank spans the joint gap so threads only engage the receiving member, pulling structural elements tightly together
• Type-17 Point - self-drilling tip bores into dense timber without pre-drilling, saving labor time and keeping workflow moving in cross-laminated and mass timber applications
• Yellow-Zinc Coating - provides corrosion resistance suitable for interior structural applications, extending service life in enclosed timber framing environments

Why This Product

• Designed specifically for cross-laminated timber and mass timber construction, this screw addresses the unique demands of CLT panel-to-beam, panel-to-wall, and floor-to-floor connections where standard fasteners fall short
• The partially-threaded configuration solves a common structural challenge - by keeping the shank smooth across the joint interface, the screw clamps members together rather than holding them apart, achieving a tighter and more structurally sound connection
• The large flat head with integrated nibs eliminates a separate countersinking step, reducing installation time on projects where hundreds or thousands of fasteners are required
• The T40 6-Lobe drive paired with a Type-17 self-drilling point means this screw is ready to drive into dense timber without pilot holes or pre-drilling in many conditions, keeping large-scale timber framing projects on schedule

Specifications

• Brand: Simpson Strong-Tie
• Screw Length: 12-1/2 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
• Finish: Yellow-Zinc Coated
• Measurement Unit: Pack

Available Pack Options

• SDCP271212-R25: 25 Pk
• SDCP271212: 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

Frequently Asked Questions

Why is the screw only partially threaded?

The partial thread design - with 3-1/8 in. of thread length on a 12-1/2 in. screw - means the threads only engage the receiving timber member. The smooth, unthreaded shank spanning the joint allows the screw to clamp both members tightly together, which is a structural requirement in cross-laminated and mass timber applications.

Do I need to pre-drill before installing this screw?

The Type-17 point is a self-drilling tip designed to bore into dense timber, which can reduce or eliminate the need for pre-drilling in many interior timber applications. Always follow applicable building codes and the manufacturer's installation guidelines for your specific project conditions.

What drive bit does this screw require?

This screw uses a T40 6-Lobe (Torx-style) drive. A T40 bit is required for installation and is not included with the screws. The 6-Lobe interface provides high torque transfer and reduces cam-out during driving, which is especially important when driving long structural screws into dense timber.

Is this screw suitable for outdoor or exposed applications?

The Yellow-Zinc coating on this screw is designed for interior structural applications. For outdoor, exposed, or pressure-treated lumber environments where higher corrosion resistance is required, a different coating or material specification would be appropriate. Consult the applicable code requirements and manufacturer data for your specific exposure conditions.

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