The Simpson Strong-Drive SDCP Timber-CP Screw is a structural fastener engineered for cross-laminated timber construction, mass timber construction, and general interior framing applications. With a yellow-zinc coated finish, a flat head profile with underhead nibs for clean countersinking, and a Type-17 cutting point for efficient penetration, this partially-threaded screw is built to pull structural members together with superb holding power - making it a reliable choice for demanding timber framing and panel connection work.

Key Features

• Yellow-Zinc Coated Finish - provides corrosion resistance suited for general interior structural applications, helping maintain the integrity of connections over time
• 4" Length with 2" Thread Length - the partial-thread design allows the screw to draw structural members tightly together, reducing gaps and improving joint strength in mass timber assemblies
• 0.390" Head Diameter (0.7 in.) Flat Head with Underhead Nibs - the large flat head seats flush and cleanly into the timber surface while the nibs lock the head against rotation during installation
• 0.275" Shank Diameter - a robust shank cross-section delivers structural-grade holding power appropriate for load-bearing timber connections
• T40 6-Lobe Drive Type - the 6-lobe Torx drive reduces cam-out during installation, giving installers better torque transfer and control compared to standard drive types
• Type-17 Cutting Point - the self-drilling point bores into timber efficiently, reducing splitting and eliminating the need for pre-drilling in many applications
• Partially Threaded Design - threads engage only the receiving member, pulling structural panels and beams tightly together for tight, secure cross-laminated timber and mass timber connections

Why This Product

• Designed specifically for cross-laminated timber (CLT) and mass timber construction - this is not a general-purpose wood screw but a purpose-built structural fastener that meets the demands of engineered timber systems
• The T40 6-lobe drive paired with the Type-17 point gives installers a faster, more controlled driving experience - less slippage, less splitting, and cleaner seating in dense timber members
• The flat head with underhead nibs countersinks cleanly without pre-grinding, saving labor time on wall-to-wall, floor-to-floor, and panel-to-beam connections where a flush surface is required
• Yellow-zinc coating delivers corrosion protection appropriate for interior structural applications, making this screw a dependable choice for long-term performance in timber framing and lap joint assemblies

Specifications

• Brand: Simpson Strong-Tie
• Finish: Yellow-Zinc Coated
• Length: 4 in.
• Head Diameter: 0.7 in.
• Shank Diameter: 0.275 in.
• Drive Type: T40 6-Lobe
• Head Type: Flat Head with Nibs
• Thread Length: 2 in.
• Point Type: Type-17 Point
• Measurement Unit: Pack

Available Pack Options

• SDCP27400-R30: 30 Pk
• SDCP27400: 250 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
• Cross-laminated timber (CLT) construction
• Mass timber construction
• General interior structural applications

Frequently Asked Questions

What type of drive tool is required for this screw?

This screw uses a T40 6-lobe (Torx) drive, so you will need a T40 bit to install it. The 6-lobe design provides excellent torque transfer and minimizes cam-out during high-torque driving into dense timber materials.

Does this screw require pre-drilling before installation?

The Type-17 cutting point is designed to bore into timber as the screw is driven, which reduces the need for pre-drilling in many timber applications. However, pre-drilling may be advisable in certain dense wood species or near edges to further reduce the risk of splitting.

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

The partial-thread design - featuring a 2 in. thread length on a 4 in. screw - means the threads engage only the receiving member while the smooth shank passes through the first member. This allows the screw to clamp the two members tightly together, which is essential for strong, tight joints in cross-laminated timber and mass timber assemblies.

What does the yellow-zinc coating provide?

The yellow-zinc coated finish offers corrosion resistance suitable for general interior structural applications. It helps protect the fastener from environmental moisture and oxidation encountered in interior timber framing, panel-to-beam, and ledger connection installations.

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