What are Simpson Strong-Tie SDWS Timber Screws? And Other FAQ
When your project calls for serious holding power, Simpson Strong-Tie SDWS timber screws are built to handle demanding wood-to-wood connections with less hassle than traditional lag bolts. Simpson Strong-Tie SDWS timber screws are heavy-duty fasteners designed for dense wood-to-wood connections. Timber screws are a faster and more efficient replacement for your standard lag bolts or structural nails. These timber screws feature a heavy-duty shank and deep threads for high load capacity and maximum pullout strength. Their sawtooth point eliminates the need for pre-drilling, and the washer head creates a large load-bearing surface with a flush, countersunk finish.
Also known as timber bolts, these fasteners are used in many wood-to-wood structural applications, such as decks, fences, pavilions, pergolas, guardrails, and more. Their deep 6-lobe star drive recess allows for easy, quick, and efficient driving that significantly reduces your installation time when compared to traditional lag bolts.
How do timber screws compare to lag bolts?
Simpson Strong-Tie SDWS Timber Screws are structural replacements for many lag bolt and structural nail applications. Their deep threads engage more wood fibers than a traditional lag bolt, which often allows them to achieve comparable or even higher withdrawal (pullout) values.
| Feature | SDWS Timber Screws | Lag Bolt |
| Pre-drilling Required | No | Yes |
| Washer Required | No | Yes |
| Drive Style | T40 Star Drive | Hex Head |
Why should you use a timber screw instead of a lag bolt?
When installing a lag bolt, you have to drill a pilot hole, drill a clearance hole, add a washer, and drive the lag bolt into the wood. When working on large projects with a need for many lag bolt installations, this can consume much of your time. The SDWS timber screw features a sawtooth point and deep threads that eliminate the need for pre-drilling without sacrificing strength and holding power. Using the Simpson Strong-Tie SDWS timber screws instead of lag bolts will significantly reduce your installation time.
Are the Simpson Strong-Tie SDWS timber screws corrosion-resistant?
Yes. SDWS timber screws are coated with a proprietary double-barrier finish that delivers corrosion protection comparable to hot-dip galvanization, making them well-suited for outdoor projects and for use with preservative-treated lumber. These screws are available in tan to blend with lumber for a more discreet appearance, or in black for a clean, finished look.
For high corrosion environments, such as coastal areas, these are also available in stainless steel.
Do I need a special drill bit to install the SDWS timber screws?
No. These timber screws install with a standard T40 6-lobe star drive drill bit. Don't have one? No problem! Each package of the SDWS timber screws comes with a drill bit included. Note: The single-screw option does not include a drill bit
What sizes are available?
All SDWS timber screws feature a shank diameter of 0.220" and a head diameter of 0.76" while the length ranges from 3" to 10" in tan and 3" to 16" in black.
Can these screws be used for structural wood connections?
Yes. Simpson Strong-Tie SDWS Timber Screws are designed for heavy-duty wood-to-wood connections and can be used in many structural fastening applications.
