The Simpson Strong-Tie Titen HD 1/4-in. x 3-in. Type 316 Stainless-Steel Heavy-Duty Screw Anchor, 50-Pack (THDC25300H6SS) is a heavy-duty screw anchor built for fastening fixtures into concrete and masonry where corrosion resistance matters as much as holding power. This is a heavy-duty screw anchor designed for anchoring structural or mechanical components into concrete and masonry in exterior and corrosive environments. Model Number: THDC25300H6SS. If you are mounting hardware in damp, coastal, chemical-exposed, or otherwise aggressive conditions, this anchor is aimed directly at that kind of work.

What makes this Titen HD screw anchor useful on the job is that it combines fast installation with serious material selection. The 1/4 in. diameter anchor installs into a 1/4 in. drilled hole, uses a 3/8 in. wrench size, and is sized at 1/4 in. x 3 in. for applications where you need a smaller-diameter anchor but still want a heavy-duty concrete and masonry fastening solution. Simpson calls out fast and efficient installation, and the product is designed to install with standard-sized ANSI tolerance carbide drill bits instead of a special proprietary bit. That saves time and cuts down on jobsite hassle.

The design is doing more than just threading into a hole. Simpson specifies an undercutting thread design that efficiently transfers load to the base material, and product listings also call out serrated cutting teeth for easier installation. In plain terms, the anchor is made to bite cleanly into the concrete or masonry rather than relying on an expansion mechanism. That matters when you want a secure mechanical anchor without the added expansion behavior associated with some other anchoring styles.

Material choice is the big story here. This version uses Type 316 stainless steel, which is the premium option in the Titen HD stainless line for saltwater exposure, chemical exposure, and other highly corrosive conditions. Simpson specifically positions Type 316 as the optimal choice for extreme environments, while Type 304 is intended for less severe wet or damp conditions. If the job is near the coast, around treated lumber, on a wastewater site, or anywhere corrosion can quietly eat standard hardware alive, moving up to 316 is the smart decision.

Jobsite practicality is solid too. The hex-washer head eliminates the need for a separate washer and leaves a cleaner installed appearance. Installation is simple: drill the hole with the same nominal diameter as the anchor, insert the anchor through the fixture, and tighten until the hex-washer head contacts the fixture. For this 1/4 in. model, Simpson lists a recommended steel fixture hole size of 3/8 in. to 7/16 in. and a minimum hole-depth overdrill of 1/8 in. Those details matter because they help the anchor tap properly and give the dust somewhere to go.

This anchor is also backed by recognized testing. Simpson lists testing to ACI 355.2, AC193, and AC106, and Tool Nut notes qualification for static and seismic loading conditions. For pros working under inspection, engineering review, or code-driven specifications, that is not just a nice extra. It is often the difference between using a generic fastener and using an anchor that actually belongs on the print.

The trade fit is broad but specific. Simpson lists mechanical, electrical, and plumbing among the target applications, and the product also makes sense anywhere a contractor is fastening railing posts, ledgers, brackets, or hardware to concrete and masonry in outdoor service. This is a good fit for MEP installers, general contractors, marine-adjacent work, exterior carpentry, and repair crews who need a corrosion-resistant concrete anchor that installs quickly with common tools.

One important note worth saying plainly: this is a one-time-use concrete screw anchor. Simpson cautions against reinstalling it because repeated installation can wear the threads and reduce load capacity. That is standard good practice for this kind of anchor, but it matters even more when you are building around performance expectations. Buy it for permanent fastening, install it correctly, and do not plan on reusing it.

Buy This When Corrosion Is the Real Enemy

The Simpson Strong-Tie Titen HD 1/4-in. x 3-in. Type 316 Stainless-Steel Heavy-Duty Screw Anchor, 50-Pack (THDC25300H6SS) is the kind of anchor you buy when a cheaper fastener would come back to haunt the job.

• Who it's for: Pros and serious DIYers fastening into concrete or masonry outdoors, near the coast, around chemicals, or anywhere standard steel hardware does not belong.
• Why it stands out: You get Type 316 stainless construction, code-recognized testing, and quick concrete screw installation without needing a special bit.
• Worth knowing: This is a permanent-use anchor, not a reusable one. Install it once, install it right, and move on.

• What base materials is this anchor designed for? It is designed for concrete and masonry applications.
• What drill bit size does this model require? This THDC25300H6SS anchor uses a 1/4 in. drill bit diameter.
• Can this anchor be used in corrosive or coastal environments? Yes. This version is made from Type 316 stainless steel and is intended for exterior or corrosive environments, including saltwater and chemical exposure.
• Can I remove and reinstall the anchor? No. Simpson specifies that Titen HD screw anchors are one-time-use only because repeated installation can reduce thread condition and load capacity.