The Simpson DIA256SS Drop-In Internally Threaded Anchor is a flush-mount expansion anchor built for solid concrete applications where a clean, low-profile installation is required. Manufactured by Simpson from Type 316 stainless steel throughout - anchor body, expander plug, and thread - this internally threaded anchor delivers secure, lasting performance in environments where corrosion resistance is critical, including coastal, chemical-exposure, and high-moisture settings. Designed for use with 1/4-in. threaded rod, it installs flush with the surface for a finished look without protruding hardware.

Key Features

• Flush-mount expansion anchor for concrete applications - sits level with the surface after installation, providing a clean finish with no exposed hardware above the base material
• Hand- and power-setting tools available - gives installers flexibility to use the method that best suits the job, making installation fast, easy, and economical
• Fixed-depth stop bit compatible - helps drill to the correct depth every time, reducing the risk of oversized holes that can compromise anchor set and load capacity
• Internally threaded for 1/4-in. rod - accepts 1/4-in. threaded rod with 20 TPI UNC threading, with minimum thread engagement equal to the nominal diameter of the threaded insert for a reliable connection
• Type 316 stainless steel construction - the anchor body, expander plug, and thread are all Type 316 stainless steel, offering superior corrosion resistance compared to standard carbon steel anchors in demanding or corrosive conditions

Why This Product

• Built for corrosive environments - the all-Type-316 stainless steel construction - body, plug, and thread - makes this anchor a reliable choice for installations exposed to moisture, chemicals, or coastal conditions where standard anchors are prone to premature failure
• Consistent, repeatable installation - compatibility with a fixed-depth stop bit and the availability of both hand and power setting tools means installers can achieve a correct, fully set anchor efficiently across multiple holes without guesswork
• Clean flush-mount finish - the drop-in design sits level with the concrete surface, making it well-suited for applications where a protruding anchor would interfere with attached components or finished appearances
• Trusted engineering for solid concrete anchoring - Simpson's DIA series drop-in anchor is engineered specifically for flush-mount anchoring in solid base materials, giving contractors and builders confidence in the connection when attaching 1/4-in. threaded rod assemblies

Specifications

• MPN: DIA256SS
• Brand: Simpson Strong-Tie
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Component Material, Anchor Body: Type 316
• Component Material, Expander Plug: Type 316
• Component Material, Thread: UNC
• Bolt/Rod Diameter: 1/4 in.
• Drill Bit Diameter: 3/8 in.
• Length: 1 in.
• Thread Length: 3/8 in.
• TPI: 20
• Packaging: Packs of 100 and Cartons of 500

Approved Applications

• Flush-mount anchoring in solid concrete base materials
• Applications requiring 1/4-in. threaded rod connections
• Environments where corrosion resistance is critical, such as coastal, chemical, or high-moisture settings

Frequently Asked Questions

What size drill bit is required to install the DIA256SS anchor?

A 3/8-in. drill bit is required to bore the correct hole for this anchor. Using an oversized hole will make it difficult to set the anchor and will reduce the anchor's load capacity.

What rod or bolt diameter is compatible with this drop-in anchor?

The DIA256SS is designed for use with 1/4-in. threaded rod. The minimum thread engagement should be equal to the nominal diameter of the threaded insert.

Why is Type 316 stainless steel used for this anchor?

Type 316 stainless steel is used for the anchor body, expander plug, and thread, providing superior corrosion resistance compared to standard stainless grades - making it well-suited for demanding or corrosive environments.

What setting tools are needed to install this anchor?

Both hand- and power-setting tools are available for installing the DIA256SS, offering fast, easy, and economical installation. A fixed-depth stop bit is also available to help ensure the hole is drilled to the correct depth every time.

Note: Product dimensions may differ from picture. Please see item description for specifications.