The Simpson HDIA Hollow Drop-In Internally Threaded Anchor from Simpson is a flush-mount expansion anchor engineered for attaching 1/2-inch threaded rod to overhead support systems including conduit, cable trays, pipe hangers, fire sprinklers, and suspended lighting. Its expansion design makes it equally effective in hollow base materials such as CMU and hollow-core plank and in solid base materials such as brick, normal-weight concrete, and lightweight concrete - giving installers a single, versatile anchor solution across a wide range of ceiling and structural substrates. Installation is straightforward using a dedicated setting tool, and the internally threaded barrel allows the bolt or rod to be removed and reinserted without disturbing the anchor.

Key Features

• Expansion design compatible with hollow and solid base materials - anchors securely into CMU, hollow-core plank, brick, normal-weight concrete, and lightweight concrete, so one anchor SKU covers multiple jobsite conditions without substitution.
• Internally threaded barrel - accepts a 1/2-inch threaded rod at 13 TPI and allows easy bolt removal and reinstallation, reducing rework time during adjustments or system changes.
• Flush-mount profile - sits level with the substrate surface after setting, keeping overhead installations clean and code-compliant where protrusion is not acceptable.
• Die-cast Zamac 3 alloy shell with carbon-steel cone - combines a corrosion-resistant shell material with a hardened cone for consistent, reliable expansion performance during setting.
• Suitable for conduit, cable trays, pipe supports, fire sprinklers, and suspended lighting - purpose-matched to the most common mechanical, electrical, and plumbing overhead suspension applications, eliminating the need to source application-specific anchors.
• Compatible with dedicated setting tools (HDIASTH50 for hollow materials, HDIASTS50 for solid materials) - proper tool pairing ensures correct expansion and full load engagement, protecting installation integrity from the first anchor set.

Why This Product

• One anchor, multiple substrates - the expansion design works in both hollow materials like CMU and hollow-core plank and solid materials like brick and concrete, reducing the number of anchor types a contractor needs to stock and manage across mixed-substrate projects.
• Built for the most demanding overhead suspension applications - approved for use with fire sprinkler attachment points, pipe support hangers, conduit and cable tray systems, and suspended lighting, making this a dependable choice for mechanical, electrical, and plumbing trades.
• Internally threaded for serviceability - unlike non-removable anchor styles, the threaded interior allows the rod or bolt to be backed out and replaced without disturbing the set anchor, which directly reduces labor cost on long-term or phased installations.
• Engineered by a trusted structural connector manufacturer - Simpson brings purpose-built design to every component, including matched setting tools and a construction suited to consistent expansion performance across normal-weight and lightweight concrete as well as masonry.

Specifications

• Manufacturer: Simpson Strong-Tie
• MPN: HDIA50
• Bolt/Rod Diameter: 1/2 in.
• Length: 1-3/4 in.
• Drill Bit Diameter: 3/4 in.
• Threads Per Inch (TPI): 13
• Shell Material: Die-cast Zamac 3 alloy
• Cone Material: Carbon steel
• Packaging: Packs of 50 and Cartons of 250

Approved Applications

• Suspending conduit and cable trays from concrete and masonry ceilings
• Pipe support hangers in mechanical and plumbing installations
• Fire sprinkler system attachment points
• Suspended lighting fixture installations
• Use in hollow base materials including CMU and hollow-core plank
• Use in solid base materials including brick, normal-weight concrete, and lightweight concrete

Frequently Asked Questions

What rod or bolt size does the Simpson HDIA50 accept?

The HDIA50 is designed to accept a 1/2-inch diameter threaded rod or bolt, with 13 threads per inch (TPI).

What base materials is the HDIA50 compatible with?

The HDIA50 expansion anchor is compatible with both hollow and solid base materials, including CMU, hollow-core plank, brick, normal-weight concrete, and lightweight concrete.

What setting tools are required to install the HDIA50?

The HDIA50 requires a dedicated setting tool for proper installation. Use the HDIASTH50 setting tool for hollow materials or the HDIASTS50 setting tool for solid materials.

What drill bit size is needed to install the HDIA50?

A 3/4-inch diameter drill bit is required to prepare the hole for the HDIA50 anchor prior to installation.

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