The Simpson Strong-Drive SDCF Timber-CF Screw (0.390 x 6-1/4", Black E-Coat) is a redesigned structural fastener engineered specifically for cross-laminated timber (CLT), mass timber construction, and general interior applications. Built to deliver uncompromised strength in demanding structural assemblies, this screw combines precision engineering with a sleek black e-coat finish that suits both performance and aesthetic requirements. Whether you are fastening heavy timber beams, reinforcing glulam members, or connecting engineered wood components, this screw provides the holding power and installation efficiency that structural work demands.

Key Features

• SawTooth Point - ensures fast, clean starts that reduce installation torque and eliminate the need for predrilling in most applications, saving time and labor on the job site.
• Flat Head with Underhead Nibs (0.725" head diameter) - the nibs pull the head cleanly into the wood surface during driving, enabling precise countersinking and a flush, professional finish in timber and CLT assemblies.
• Black E-Coat Electrocoating - enhances the visual appearance of exposed fasteners while also working in combination with the screw's optimized hardness profile to reduce the risk of brittle fracture, supporting reliable long-term performance.
• Optimized Hardness Profile - engineered to mitigate brittle fracture risk, giving you confidence in structural connections that must perform consistently over time.
• T50 6-Lobe Drive Type - provides superior bit engagement and reduced cam-out compared to common drive types, allowing controlled, high-torque driving in dense timber materials.
• 6" Thread Length on a 6-1/4" Overall Length - maximizes thread engagement in the receiving member to develop full structural holding capacity across the connection.
• 0.290" Shank Diameter with 0.390" Outer Diameter - the shank geometry supports structural load transfer while the thread profile bites firmly into CLT, glulam, and other engineered wood products.
• T50 Driver Bit Included - the correct installation bit ships with the screw, so you are ready to drive immediately without sourcing a separate accessory.

Why This Product

• Designed specifically for mass timber and cross-laminated timber construction, this screw addresses the unique demands of CLT and glulam applications where standard fasteners may lack the thread engagement, head geometry, or material profile needed for structural connections.
• The SawTooth point and reduced installation torque mean you can drive these screws efficiently into dense engineered wood and heavy timber without predrilling in most situations, cutting installation time on large-scale timber framing projects.
• The black e-coat finish is not purely cosmetic - it works alongside the screw's optimized hardness profile to help reduce brittle fracture risk, a critical concern in structural timber fastening where connection integrity must be maintained over the life of the building.
• The large flat head with underhead nibs produces a clean, flush countersink in timber surfaces, making this screw well suited for exposed structural applications such as surface splines, beam reinforcement, and wall-to-wall connections where appearance and fit matter.

Specifications

• Brand: Simpson Strong-Tie
• Outer Diameter x Length: 0.390 x 6-1/4"
• Length: 6-1/4 in.
• Shank Diameter: 0.290 in.
• Head Diameter: 0.725 in.
• Thread Length: 6 in.
• Head Type: Flat Head with Nibs
• Drive Type: T50 6-Lobe
• Point Type: SawTooth Point
• Coating: E-coat Electrocoating
• Finish: E-coat Electrocoating
• Color: Black
• Country of Origin: Taiwan

Available Pack Options

• SDCF10X160-R30: 30 Pk - includes T50, 6-lobe driver bit (replacement bit: BIT50T-2-R1)
• SDCF10X160-R30 -6: 180 Pk - includes T50, 6-lobe driver bit (replacement bit: BIT50T-2-R1)
• SDCF10X160: 250 Pk - includes T50, 6-lobe driver bit (replacement bit: BIT50T-2-R1)

Approved Applications

• Mass Timber / Cross-Laminated Timber (CLT)
• Heavy Timber
• Glulam
• Timber Framing
• Engineered Wood - Multi-Ply Fastening
• Engineered Wood
• Beam Reinforcement
• Surface Splines
• Fastening Wood-to-Wood
• Fastening Wood-to-Steel
• Fastening Support Beams
• Fastening Butt Joists
• Fastening Wall-to-Wall
• Fastening Floor-to-Floor
• Fastening Stud-to-Plate
• Fastening Simpson Strong-Tie Connectors
• General Interior

Frequently Asked Questions

Do I need to predrill before installing these screws in CLT or heavy timber?

In most applications, predrilling is not required. The SawTooth point is engineered to start fast and reduce installation torque, allowing the screw to self-start in cross-laminated timber, glulam, and other engineered wood products without a pilot hole in the majority of cases.

What drive bit does this screw use, and is one included?

This screw uses a T50 6-lobe (Torx-style) drive bit. A T50, 6-lobe driver bit is included with the screw. If you need a replacement bit, the compatible replacement is the BIT50T-2-R1.

Why does the head have underhead nibs, and what do they do?

The underhead nibs on the flat head are designed to cut into the wood surface as the screw is driven home. This action pulls the head cleanly into the material, producing a precise countersink and a flush finish - an important detail for exposed structural and architectural timber applications where surface appearance matters.

What is the purpose of the black e-coat finish on a structural screw?

The black e-coat electrocoating serves two roles. First, it provides a clean, dark appearance that suits exposed timber construction where fastener aesthetics are considered. Second, when combined with the screw's optimized hardness profile, the e-coat finish helps mitigate the risk of brittle fracture, contributing to the screw's reliability and long-term structural performance in demanding timber connections.