The Simpson Strong-Bolt 2 5/8 in. x 8-1/2 in. Wedge Anchor in Type 304 Stainless Steel is a wedge-type expansion anchor engineered for high-performance structural connections in both cracked and uncracked concrete. Built to perform under seismic and high-wind conditions, this anchor features dual undercutting embossments on each clip segment that enable secondary expansion should a crack form and intersect the anchor location - significantly increasing load-carrying capacity if the hole expands. The all-stainless construction delivers long-lasting corrosion resistance across a wide variety of service environments where standard carbon steel anchors may fail prematurely.

Key Features

• Dual undercutting embossments on each clip segment - enable secondary expansion if a crack intersects the anchor, so the anchor continues to carry load even as concrete conditions change
• Code listed for cracked and uncracked concrete applications - gives engineers and inspectors a straightforward path to approval on projects requiring compliant anchoring solutions
• Qualified for seismic design categories A through F and high-wind conditions - suitable for the most demanding structural environments without requiring special engineering exceptions
• Chamfered top design - prevents mushrooming during installation, making the anchor easier to drive and helping ensure a clean, consistent result every time
• Suitable for horizontal, vertical, and overhead applications - provides installation flexibility across a wide range of structural concrete anchoring scenarios
• Standard ANSI fractional sizing (5/8 in. diameter) - fits standard fixtures and installs with a common 5/8 in. drill bit and 15/16 in. wrench, so no specialty tooling is required
• Tested per ACI355.2 and AC193 - independently verified performance standards give confidence that load ratings are reliable and code-defensible
• Type 304 Stainless Steel construction throughout (body, nut, and washer) - provides long-lasting corrosion resistance for service environments where moisture, chemicals, or outdoor exposure would degrade standard hardware

Why This Product

• Built for cracked concrete without sacrificing load performance - the dual undercutting clip embossments actively respond to crack formation at the anchor location, maintaining holding strength in conditions that would compromise conventional expansion anchors
• Covers the full range of seismic risk zones - with qualification across seismic design categories A through F, this wedge anchor is appropriate for structural concrete connections in virtually any geographic region with seismic or high-wind design requirements
• All-stainless material stack reduces long-term maintenance risk - because the anchor body, nut, and washer are all Type 304 Stainless Steel, there is no mixed-metal corrosion concern and no need to source matching hardware separately
• Installs with standard tooling, no learning curve required - the 5/8 in. drill bit size and 15/16 in. wrench are common on most job sites, and the chamfered top minimizes installation errors, making this anchor practical for both routine and critical structural work

Specifications

• Model Number: STB2-62812S4F20
• Size: 5/8 in. x 8-1/2 in.
• Anchor Size: 5/8 in. x 8-1/2 in.
• Drill Bit Diameter: 5/8 in.
• Thread Length: 6 in.
• Coating / Material: Type 304 Stainless Steel
• Anchor Body Material: Type 304 Stainless Steel
• Nut Material: Type 304 Stainless Steel
• Washer Material: Type 304 Stainless Steel
• Clip Material: Type 304 or Type 316 Stainless Steel
• Packaging: Packs of 20 and Cartons of 40

Approved Applications

• Cracked concrete structural connections
• Uncracked concrete structural connections
• Seismic zone installations requiring code-listed anchors
• High-wind condition applications
• Service environments requiring long-lasting corrosion resistance

Frequently Asked Questions

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

Yes. The Strong-Bolt 2 is code listed for both cracked and uncracked concrete applications. Its dual undercutting embossments on each clip segment allow secondary expansion if a crack forms and intersects the anchor location, significantly increasing the anchor's ability to carry load if the hole expands.

What material is this anchor made from, and why does it matter?

The anchor body, nut, and washer are all Type 304 Stainless Steel. The clip is Type 304 or Type 316 Stainless Steel. This all-stainless construction provides long-lasting corrosion resistance for a wide variety of service environments where standard carbon steel anchors may corrode prematurely.

What drill bit size is required to install the STB2-62812S4F20?

A 5/8 in. diameter drill bit is required for proper installation of this wedge anchor.

Is this anchor approved for seismic and high-wind applications?

Yes. The Strong-Bolt 2 wedge-type expansion anchor is an optimal choice for high performance even in seismic and high-wind conditions, and it is code listed to support these demanding structural requirements.

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