The Simpson Strong-Bolt 2 1/2 in. x 4-1/4 in. Wedge Anchor in Type 316 Stainless Steel is a wedge-type expansion anchor built for high-performance concrete fastening in the most demanding conditions. Dual undercutting embossments on each clip segment enable secondary expansion should a crack form and intersect the anchor location, significantly increasing the anchor's ability to carry load even as the hole expands. With full Type 316 Stainless Steel construction throughout every component - anchor body, nut, washer, and clip - this anchor delivers long-lasting corrosion resistance suited to a wide variety of service environments, from coastal exposures to industrial settings.

Key Features

• Code listed for cracked and uncracked concrete applications - gives installers and inspectors confidence that the anchor meets code requirements across the broadest range of concrete conditions.
• Dual undercutting embossments on each clip segment - enable secondary expansion if a crack intersects the anchor location, helping maintain load capacity and performance integrity over time.
• Qualified for static and seismic loading conditions (seismic design categories A through F) - makes this anchor a reliable choice for projects in earthquake-prone regions and high-wind environments where code-listed performance is required.
• Chamfered top designed to prevent mushrooming during installation - reduces installation errors and helps ensure a clean, consistent set every time.
• Suitable for horizontal, vertical, and overhead applications - provides installation flexibility across a wide range of structural and architectural fastening scenarios.
• Standard ANSI fractional sizing - fits standard fixtures and installs with common drill bit and tool sizes, including a 1/2 in. drill bit and 3/4 in. wrench, so no specialty tooling is required.
• Tested per ACI355.2 and AC193 - independently verified performance standards give engineers and contractors a reliable basis for design calculations and project submittals.
• Full Type 316 Stainless Steel construction throughout all components - provides superior corrosion resistance in moisture-prone, corrosive, or chemically exposed service environments where carbon steel anchors would degrade.

Why This Product

• Built to perform where ordinary anchors fall short - the dual undercutting embossment design actively responds to crack formation in concrete, maintaining load-carrying capacity in conditions that would compromise a standard wedge anchor.
• One anchor, every orientation - approved for horizontal, vertical, and overhead installations with qualification across seismic design categories A through F, this anchor reduces the need to source multiple products for complex or mixed-orientation projects.
• Stainless steel from top to bottom - with every component manufactured from Type 316 Stainless Steel, there are no mixed-metal weak points, making this anchor well suited for corrosive, wet, or marine-adjacent environments where long-term reliability matters.
• Straightforward installation with standard tooling - ANSI fractional sizing and compatibility with a common 1/2 in. drill bit and 3/4 in. wrench mean faster setup and no additional equipment investment on the job site.

Specifications

• Model No.: STB2-50414S6F25
• Coating/Material: Type 316 Stainless Steel
• Size: 1/2 in. x 4-1/4 in.
• Drill Bit Diameter: 1/2 in.
• Thread Length: 2-9/16 in.
• Component Material, Anchor Body: Type 316 Stainless Steel
• Component Material, Nut: Type 316 Stainless Steel
• Component Material, Washer: Type 316 Stainless Steel
• Component Material, Clip: Type 316 Stainless Steel
• Packaging: Packs of 25 and Cartons of 100

Approved Applications

• Cracked concrete installations
• Uncracked concrete installations
• Seismic applications requiring code-listed anchoring solutions
• High-wind condition installations
• Corrosive or moisture-prone service environments where stainless steel is required

Frequently Asked Questions

What size hole do I need to drill for the STB2-50414S6F25 wedge anchor?

This anchor requires a 1/2 in. diameter drill bit and corresponding hole to accommodate the wedge anchor properly during installation.

Is the Strong-Bolt 2 approved for use in cracked concrete?

Yes. The Strong-Bolt 2 is code listed for both cracked and uncracked concrete applications. The dual undercutting embossments on each clip segment allow for secondary expansion if a crack forms and intersects the anchor location, helping maintain load capacity even as the hole expands.

Why is Type 316 Stainless Steel used for all components of this anchor?

All components - including the anchor body, nut, washer, and clip - are manufactured from Type 316 Stainless Steel to provide long-lasting corrosion resistance across a wide variety of service environments, particularly those involving moisture, chemicals, or other corrosive conditions.

Can this anchor be used in seismic or high-wind applications?

Yes. The Strong-Bolt 2 wedge-type expansion anchor is an optimal choice for high-performance installations, and is specifically code listed for use in seismic and high-wind conditions.

Note: Product dimensions and/or thread length may differ from picture. Please see the item description above for specifications.