The Simpson Strong-Tie Strong-Drive SDCFC TIMBER-CFC Screw 0.390 x 19-5/8 in. is a heavy-duty structural fastener engineered specifically for cross-laminated timber and mass timber construction. Built to handle the demands of large-scale structural assemblies, this screw is suited for beam reinforcement, wall-to-wall connections, floor-to-floor connections, butt joints, and splitting reinforcement in interior dry environments where reliable, long-lasting fastening performance is critical.

Key Features

• Cylinder head profile - sits flush and stable against structural members, reducing surface interference and providing a clean, secure seating point in heavy timber assemblies.
• T50 6-Lobe drive - enables high-torque installation with reduced cam-out risk, so installers can drive long fasteners fully and consistently without slipping or stripping.
• Extra-long 19-5/8 in. overall length with an 18-3/8 in. thread length - delivers deep thread engagement into CLT and mass timber members, maximizing withdrawal resistance in demanding structural connections.
• Yellow zinc coating - formulated for interior, dry applications, providing corrosion resistance appropriate to controlled indoor environments such as those found in mass timber buildings.
• Approved for cross-laminated timber, mass timber, beam reinforcement, and butt joints - gives builders and engineers confidence that the fastener is purpose-built for the specific connection types common in modern timber construction.

Why This Product

• Purpose-engineered for CLT and mass timber - unlike general-purpose screws, this fastener is specifically designed and approved for the connection types that define modern mass timber construction, including wall-to-wall, floor-to-floor, and beam reinforcement applications.
• Superior withdrawal resistance through deep thread engagement - the 18-3/8 in. thread length means a significantly greater portion of the fastener is actively gripping the timber, which is essential in structural joints where pull-out forces are a primary design concern.
• Installer-friendly drive system - the T50 6-Lobe drive is designed for full torque transfer, making it practical to install long, heavy-duty screws in structural lumber without the frustration of cam-out or incomplete seating.
• Backed by Simpson Strong-Tie engineering - the fastener carries approved application designations from Simpson Strong-Tie, giving contractors, engineers, and inspectors a trusted reference point for structural fastening in cross-laminated timber and general interior mass timber projects.

Specifications

• Model Number: SDCFC271958
• Brand: Simpson Strong-Tie
• Series: Strong-Drive SDCFC TIMBER-CFC
• Length: 19-5/8"
• Shank Diameter: 0.29 in.
• Head Diameter: 0.525 in.
• Thread Length: 18-3/8 in.
• Head Type: Cylinder Head
• Drive Type: T50 6-Lobe
• Coating/Material: Yellow-Zinc Coated
• Pack Size: 50

Approved Applications

• Cross-laminated timber (CLT) construction
• Mass timber construction
• General interior applications
• Beam reinforcement
• Wall-to-wall connections
• Floor-to-floor connections
• Support beams
• Butt joints
• Splitting reinforcement

What's Included

• 50 x Simpson Strong-Tie Strong-Drive SDCFC TIMBER-CFC Screws (0.390 x 19-5/8")

Frequently Asked Questions

What type of drive does the SDCFC271958 screw require?

The SDCFC271958 uses a T50 6-Lobe drive. A T50 driver bit is required for proper installation to ensure full torque transfer without cam-out.

Is the yellow zinc coating suitable for outdoor or high-moisture environments?

No. The yellow zinc coating on the SDCFC271958 is intended for interior, dry applications only. It is not rated for exterior, wet, or corrosive environments.

What is the thread length on this screw, and why does it matter?

The SDCFC271958 features a thread length of 18-3/8". A longer thread engagement in mass timber and CLT members significantly increases withdrawal resistance, which is critical in structural connections such as beam reinforcement, butt joints, and wall-to-wall assemblies.

How many screws are included in one package of SDCFC271958?

Each package contains 50 screws, making it practical for professional structural timber projects requiring multiple fasteners per connection point.