The Simpson Rough 4X Adjustable Post Cap from Simpson is a structural post-to-beam connector built for both new construction and retrofit applications where a reliable, load-bearing connection is needed at the top of a post. Constructed from 18-gauge steel with a ZMAX galvanized finish, this adjustable post cap is engineered to create a positive connection between a beam and a post - and is always installed in pairs to achieve its intended structural performance. Designed specifically for 4x rough lumber, it offers a stronger fastening method than angled nailing or screw fastening, making it a dependable choice for exterior framing, deck posts, and treated-wood structures.

Key Features

• Eliminates nailing into end grains - removes a common weak point in post-to-beam connections, resulting in a more structurally sound joint
• Stronger than angled nailing or screw fastening - delivers superior holding strength compared to traditional field-fastening methods, supporting long-term structural integrity
• Designed for 4x rough lumber - provides a properly sized, secure fit for rough-sawn 4x posts without the need for modification or shimming
• Made from 18-gauge steel - offers a solid balance of strength and workability, suitable for demanding structural connector applications
• ZMAX galvanization offers extra corrosion resistance for exterior and treated-wood applications - helps the connector hold up in moisture-prone and chemically treated environments where standard coatings can deteriorate prematurely
• 7 in. length - provides sufficient bearing surface to distribute load effectively across the post-to-beam connection
• Installs with 0.162 in. x 3-1/2 in. nails - using the specified fasteners ensures the connection performs to its intended structural capacity

Why This Product

• A stronger connection where it matters most - by eliminating end-grain nailing and outperforming angled nailing or screw fastening, this post cap creates a more reliable beam-to-post joint that holds up under structural loads
• Built for exterior and treated-wood environments - the ZMAX galvanized coating provides enhanced corrosion resistance, making this connector well-suited for exposed deck framing, pergola posts, and other outdoor structural applications
• Flexible enough for new builds and retrofits - the adjustable design accommodates both new construction framing and existing post connections, reducing the need for multiple specialized connectors
• Domestic quality from a trusted structural connector brand - manufactured by Simpson, a name closely associated with engineered wood connectors, this post cap is made in the United States to meet the demands of professional framers and serious DIYers alike

Specifications

• MPN: AC4RZ
• Member Size: 4x rough
• Width: 4 in.
• Length: 7 in.
• Gauge: 18
• Coating/Finish: ZMAX
• Install With: 0.162 in. x 3-1/2 in. nails (sold separately)
• Country of Origin: United States

Frequently Asked Questions

What lumber size is the AC4RZ designed for?

The AC4RZ is specifically designed for use with 4x rough lumber, providing a secure and properly sized connection between the post and beam.

Why must the AC series post caps be installed in pairs?

The AC series is engineered to provide a positive connection between a beam and a post, and this connection requires two caps - one on each side - to achieve the intended structural performance. These connectors are always installed in pairs.

What makes ZMAX galvanization beneficial for this post cap?

ZMAX galvanization offers extra corrosion resistance, making the AC4RZ well-suited for exterior applications and use with treated wood, where standard coatings may be prone to premature deterioration.

What fasteners are required to install the AC4RZ?

Installation of the AC4RZ requires 0.162 in. x 3-1/2 in. nails. Using the specified fasteners ensures the connection meets its intended structural capacity.

Note: Product dimensions and/or nail or screw holes may differ from picture. Please see item description for specifications.