The Simpson 1/4 x 3 Countersunk Split-Drive Anchor Mechanically Galvanized is a one-piece carbon steel expansion anchor from Simpson engineered for fast, reliable fastening into concrete, grout-filled block, and stone. Its split-type expansion mechanism on the working end compresses as the anchor is driven into a pre-drilled hole, exerting force against the walls of the hole to create a secure mechanical hold without adhesives or secondary components. The countersunk head sits flush with the surface, making these anchors well suited for attaching wood or light gauge steel to concrete and grout-filled block in dry, interior, and non-corrosive environments.

Key Features

• One-piece split-drive expansion design - the anchor sets itself as it is driven in, eliminating the need for adhesives or additional hardware and speeding up installation.
• Countersunk head - sits flush with the surface after installation, providing a clean, low-profile finish ideal for wood and light gauge steel attachments.
• Compatible with concrete, grout-filled block, and stone - broad base-material versatility means fewer anchor SKUs needed across common masonry fastening applications.
• Mechanically galvanized carbon steel construction meeting ASTM B695, Class 55, Type 1 - delivers a consistent, durable coating that holds up in dry, interior, and non-corrosive environments where corrosion resistance is needed without the cost of stainless steel.
• 1/4 in. anchor diameter matched to a 1/4 in. drill bit - the same-size drill bit and anchor diameter creates a proper interference fit, simplifying tool selection and reducing the chance of installation error.

Why This Product

• Trusted engineering for demanding structural applications - Simpson Strong-Tie mechanical anchors are specified by contractors and engineers for performance in demanding structural fastening work, giving buyers confidence in the anchor's reliability across concrete and masonry substrates.
• Tool-driven installation with no mixing or curing - the split-drive mechanism sets mechanically as the anchor is driven, so there is no adhesive to mix, no cure time to wait for, and no secondary setting step slowing down the job.
• Flush countersunk profile for clean finished surfaces - the countersunk head design is purpose-built for applications where a protruding fastener head would interfere with the attached material or finished appearance, such as attaching wood framing or light gauge steel channels directly to a concrete slab or block wall.
• Standardized sizing simplifies procurement and layout - the 1/4 in. diameter anchor uses the same 1/4 in. drill bit, so crews can work with a single bit size across the layout, reducing setup time and the risk of mismatched tooling on the job site.

Specifications

• Brand: Simpson Strong-Tie
• MPN: CSD25300MG
• Diameter: 1/4 in.
• Length: 3 in.
• Head Type: Countersunk Head
• Head Diameter: 1/2 in.
• Drill Bit Diameter: 1/4 in.
• Material: Carbon Steel
• Coating: Mechanically Galvanized
• Finish: Mechanically Galvanized
• Galvanizing Standard: ASTM B695, Class 55, Type 1
• Packaging: Packs of 100 and Cartons of 400

Approved Applications

• Fastening into concrete surfaces
• Fastening into grout-filled block and grouted CMU
• Fastening into stone
• Attaching wood to concrete and grout-filled block surfaces
• Attaching light gauge steel to concrete and grout-filled block surfaces
• Dry, interior, and non-corrosive environments only

Frequently Asked Questions

What base materials can the Simpson CSD25300MG Split-Drive Anchor be installed in?

This anchor can be installed in concrete, grout-filled block, and stone. It is not intended for use in hollow CMU or non-solid base materials unless they are grout-filled.

What drill bit size is required for installation?

Installation requires a 1/4 in. diameter drill bit, which matches the anchor's nominal diameter for a proper interference fit as the expansion mechanism drives into the hole.

Is the CSD25300MG suitable for outdoor or high-moisture environments?

No. This anchor is designed for use in dry, interior, and non-corrosive environments only. While the mechanically galvanized finish meets ASTM B695, Class 55, Type 1, it is not rated for exterior, wet, or corrosive conditions.

What does the countersunk head design offer compared to other head types?

The countersunk head allows the anchor to sit flush with or below the surface of the material being fastened, providing a smooth surface finish. This is particularly advantageous when attaching wood or light gauge steel to concrete or grout-filled block where a protruding fastener head would be undesirable.

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