The Simpson Strong-Drive SDWS Timber Screw (Interior, 0.220 in. x 10 in., E-coat) is a heavy-duty structural wood fastener engineered for cross-laminated timber construction, mass timber assemblies, log-home construction, and general interior wood-to-wood fastening applications. Featuring an electrocoated black finish, serrated threads, and a SawTooth point, this 10-inch structural screw drives faster and with less torque than comparable lag screws - making it a reliable choice for demanding timber framing projects that require a code-listed solution.

Key Features

• SawTooth Point - enables fast starts and significantly reduces installation torque, eliminating the need for predrilling in most applications and speeding up the overall workflow
• Serrated Thread Design - reduces wood splitting and material damage during installation, protecting the structural integrity of timber members
• Low-Profile Washer Head (0.760 in. diameter) - provides maximum bearing area that pulls members together firmly, removing the need for extra washers and simplifying the fastening process
• T40 6-Lobe Drive - delivers positive bit engagement that makes driving easier, reduces cam-out, and extends driver bit life even through dense timber
• 5-1/4 TPI with 3 in. Thread Length - optimized thread geometry grips thick timber sections securely for strong, lasting connections in structural applications
• E-coat Electrocoating Finish - provides a durable black protective coating suited for interior structural assemblies, with a uniform appearance for clean finished results
• 0.220 in. Shank Diameter - a large-diameter shank delivers high load capacity in wood-to-wood connections, reducing the number of fasteners needed per joint
• Code Listed under IAPMO-UES ER-192 - meets 2018 and 2021 IRC and IBC code requirements for common wood framing applications, supporting permit-ready construction without additional engineering

Why This Product

• Built for mass timber and cross-laminated timber (CLT) construction - the 10-inch length, large shank diameter, and serrated threads are specifically designed to handle the demands of CLT panels, heavy timber framing, and log-home construction where fastener performance is critical
• Installs faster than lag screws - the SawTooth point and serrated thread geometry require less torque, meaning no predrilling in most cases and a noticeably faster installation pace on large-scale timber projects
• Eliminates extra hardware at the joint - the large-diameter washer head pulls timber members together without requiring additional washers, reducing material cost and simplifying installation steps
• Comes ready to drive - includes a T40 6-lobe driver bit so you can begin installation immediately without sourcing a separate bit, saving setup time on the job site

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter (in.): 0.220
• Length (in.): 10
• Head Type: Low Profile Head
• Head Diameter (in.): 0.760
• Drive Type: T40 6-Lobe
• Thread Type: Serrated Threads
• Thread Length (in.): 3
• TPI: 5 1/4
• Point Type: SawTooth Point
• Coating: E-coat Electrocoating
• Finish: E-coat Electrocoating
• Color: Black
• Country of Origin: Taiwan

Available Pack Options

• SDWS221000-R50: 50 Pk - includes T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)
• SDWS221000: 250 Pk - includes T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)

Approved Applications

• Fastening Wood-to-Wood
• Log-Home Construction

Frequently Asked Questions

Do I need to predrill before installing this timber screw?

In most applications, predrilling is not required. The SawTooth point is specifically designed to start fast and reduce installation torque, allowing the screw to drive directly into timber members without a pilot hole in most common wood framing scenarios.

What drive bit does this screw require, and is it included?

This screw uses a T40 6-lobe (Torx-style) drive. A T40 6-lobe driver bit is included with the screw. If you need a replacement, the compatible replacement bit is the BIT40T-134-R2.

Is this screw suitable for exterior or treated-lumber applications?

This screw carries an E-coat electrocoating finish and is designated for interior applications - including cross-laminated timber construction, mass timber assemblies, log-home construction, and general interior wood-to-wood fastening. For exterior or pressure-treated lumber applications, a different coating or screw series would be appropriate.

Is this screw code listed for structural wood framing?

Yes. The Strong-Drive SDWS Timber Screw is code listed under IAPMO-UES ER-192 and meets IRC and IBC code requirements for several common wood framing applications, supporting permit-ready structural installations.