Simpson Strong-Tie SDS25600 Strong-Drive SDS Heavy-Duty Connector Screw is a 1/4 inch x 6 inch structural wood screw built for heavy-duty connector installations, wood-to-wood fastening, and engineered wood applications. This is a heavy-duty connector screw designed for structural fastening in exterior wood construction. Model Number: SDS25600. For crews doing deck work, framing connections, or hardware installs, this fastener is made to give you structural holding power without slowing the job down with predrilling.

The main advantage here is speed without giving up control. Simpson Strong-Tie uses a Type-17 point, which helps the screw start easier in wood and cuts down on splitting. That matters when you are driving a longer 6 inch structural screw into framing members, ledgers, posts, or engineered lumber and you do not want to waste time drilling pilot holes unless the application specifically calls for them.

The drive design is just as important as the point. This screw uses a 3/8 inch hex drive and a hex head with a 0.500 inch integrated washer. In practical terms, that means better bit engagement, less chance of cam-out than a smaller recess style, and more bearing surface under the head when fastening heavy-duty Simpson Strong-Tie connectors or similar structural hardware. When you are leaning on a screw this size, that wider bearing surface is a real benefit.

The thread design is set up for structural wood fastening, not light-duty assembly. The SDS25600 uses serrated threads with 10 threads per inch and a 3-1/4 inch thread length. That combination helps the fastener pull consistently while still giving you the reach of a 6 inch overall length. It is a good fit when the job calls for deeper embedment or fastening through thicker material stacks.

For exterior use, the double-barrier coating is one of the reasons this specific version exists. It is intended for corrosion resistance in outdoor wood construction applications. If you are comparing variants within the SDS line, that coating is the differentiator on the SDS25600 versus stainless versions in the same family. It gives you an exterior-ready option when stainless is not required by the application or environment.

Jobsite practicality is strong here too. Simpson notes that the head is stamped with the company mark and fastener length for easier identification after installation. That sounds small, but when you are inspecting a connection or sorting installed hardware on a job with multiple screw lengths, that stamp saves second-guessing. The manufacturer also recommends using a low-speed 1/2 inch drill with a 3/8 inch hex driver for installation, which tells you exactly how this fastener is intended to be run for best control.

This screw is part of Simpson Strong-Tie's Strong-Drive SDS heavy-duty connector screw platform, a line used widely in structural wood construction. It is commonly used with heavy-duty Simpson Strong-Tie connectors, but it is also suited to wood-to-wood and engineered wood fastening where a 1/4 inch structural screw with hex head drive makes sense. Replacement driver bit model BITHEXR38-R1 is specified for this drive style.

Who should buy it? Contractors, deck builders, framers, remodelers, and serious DIY users working on structural wood connections. If you need a long structural fastener for exterior wood projects and want the convenience of a screw instead of the hassle of slower traditional connector fastening methods, the SDS25600 is the kind of fastener you keep on hand because it solves real installation problems quickly.

Simpson Strong-Tie SDS25600 Strong-Drive SDS Heavy-Duty Connector Screw Gets the Structural Job Done

This is the kind of structural screw you buy when regular construction screws are not even in the conversation.

• Who it's for: Pros and serious DIY builders doing deck framing, connector installs, engineered wood fastening, and other structural wood work.
• Why it stands out: The Type-17 point speeds up installs, the 3/8 inch hex drive holds up better under load, and the integrated washer head makes sense for hardware and structural connections.
• Worth knowing: This SDS25600 carton is a bulk quantity of 600 screws, so it is a good fit for active shops and crews. You will need the proper 3/8 inch hex driver, and the replacement bit is sold separately.

• What is the Simpson Strong-Tie SDS25600 Strong-Drive SDS Heavy-Duty Connector Screw used for? It is used for heavy-duty connector installations, wood-to-wood fastening, and engineered wood applications.
• Does this screw require predrilling? Simpson Strong-Tie states the Type-17 point enables easy driving with no predrilling and minimal splitting in wood applications.
• What driver does it use? It uses a 3/8 inch hex drive, and Simpson recommends a low-speed 1/2 inch drill with a 3/8 inch hex driver for installation.
• Is this version coated for exterior use? Yes. The SDS25600 uses a corrosion-resistant double-barrier coating intended for exterior wood construction applications.