Description

Key Features

Stronger 90° Joints

The Simpson Strong-Tie A21Z Angle reinforces wood-to-wood corners where angled nailing alone is not enough. It helps keep joints square and adds dependable strength for repairs, blocking, and light structural connections.

Compact 18-Gauge Bracket

At 2 in. x 1-1/2 in. x 1-3/8 in., this framing angle fits tight connection points without adding much bulk. The 18-gauge steel body gives you useful reinforcement for common framing and repair work.

ZMAX Corrosion Resistance

The ZMAX coating is the reason to choose the A21Z over the standard A21. It is better suited for exterior work and treated lumber where basic galvanized hardware may not be enough.

Overview

The Simpson Strong-Tie A21Z Angle is a compact framing angle made for wood-to-wood connections that need a clean, reinforced 90-degree tie. This is an angle bracket designed for fastening wood-to-wood joints in framing, repairs, and general connection work. Model Number: A21Z. If you are tying blocking, a small post or stud connection, or a repair point where straight, repeatable placement matters, this connector does the job without taking up much space.

What makes the A21Z useful is simple: it gives you a stronger and straighter connection than relying on angled nails or screws alone. The 18-gauge steel body is sized at 2 inches by 1-1/2 inches by 1-3/8 inches, so it fits small corners and tight assemblies while still adding structure where the joint needs help. For installers, that means faster repeat work and fewer crooked connections when lining up framing members.

The ZMAX finish matters if this angle is going into outdoor work or pressure-treated lumber. Simpson Strong-Tie calls out ZMAX-coated connectors for projects where moisture is present and for treated-wood applications. In practical terms, that makes the A21Z a better pick than a basic zinc-galvanized angle when the connection may see weather exposure or more aggressive wood treatment chemicals.

This angle is part of Simpson Strong-Tie’s broader A-angle family, which is built specifically for 90-degree connections across a range of load requirements. For the A21Z size, published load-table data for the A21 lists allowable loads up to 430 lb uplift and 165 lb lateral in Douglas Fir/Southern Pine, and 360 lb uplift and 140 lb lateral in Spruce-Pine-Fir/Hem-Fir when installed with the specified fasteners. That is the kind of information that matters when you are choosing a connector based on more than just fit.

Installation is straightforward, but this is one of those products where the fastener choice is part of the connector system. Simpson says to use all specified fasteners. Lowe’s lists installation with 10d x 1-1/2 in. nails or #9 x 1-1/2 in. Strong-Drive SD screws, and the load tables reference SD9112 fasteners for the A21. That matters because connector performance depends on using the right hole fill and the right fastener type, not just getting something through the holes.

From a design standpoint, this is a simple part done right. The formed 90-degree bend, compact footprint, and prepunched holes make it easy to position and repeat across multiple assemblies. It is not a heavy structural bracket for major post or beam work, and it is not pretending to be. It is a compact framing connector for light-duty structural reinforcement and repair where consistency, corrosion resistance, and ease of installation matter more than sheer size.

The best buyer for the Simpson Strong-Tie A21Z Angle is a framer, remodeler, deck builder, maintenance pro, or serious DIYer working on wood framing and repair. It is especially useful when you want a small angle bracket for fastening blocking, tying members at right angles, or cleaning up a repair with a connector that looks intentional instead of improvised.

Keep Small Framing Connections Straight

The compact shape is the whole point here. The Simpson Strong-Tie A21Z Angle gives you a simple way to reinforce a small corner connection without reaching for a bigger bracket than the job needs.

• Designed for wood-to-wood fastening at 90 degrees
• 18-gauge steel balances fit, stiffness, and easy handling
• Prepunched holes help keep placement consistent from one connection to the next

Built for Real Wood-to-Wood Installation

This type of framing angle is made to solve a common jobsite problem: a small wood joint that needs more holding power and better alignment than toe-nailing can provide by itself.

• Install with 10d x 1-1/2 in. nails or #9 x 1-1/2 in. Strong-Drive SD screws per supplementary product data
• Simpson instructs users to install with all specified fasteners
• ZMAX coating is better suited for exterior and treated-wood applications

Know the Size Before You Build

On small connectors, dimensions decide whether the part works or becomes a return. The A21Z uses a 2-inch leg, a 1-1/2-inch leg, and a 1-3/8-inch length, so it is meant for compact tie points rather than wide bearing connections.

• W1: 2 in.
• W2: 1-1/2 in.
• L: 1-3/8 in.

Key Specifications

Tool Type	Framing angle
Application	Fastening wood-to-wood
Material	Steel
Gauge	18 ga.
Finish	ZMAX coating
Width 1	2 in.
Width 2	1-1/2 in.
Length	1-3/8 in.
Number of Holes	4
ACQ Approved	Yes
Allowable Uplift Load	430 lb (DF/SP), 360 lb (SPF/HF)
Allowable Lateral Load	165 lb (DF/SP), 140 lb (SPF/HF)

Compatibility

Materials

Designed for wood-to-wood connections.

Fastener Options

Supplementary data lists 10d x 1-1/2 in. nails or #9 x 1-1/2 in. Strong-Drive SD screws.

Treated Lumber Use

ZMAX-coated version is intended for exterior and treated-wood applications where added corrosion resistance is needed.

Built For

Carpentry Construction Deck Building Remodeling General Repairs Wood Framing Blocking and Bracing DIY / Hobbyist

Pro Tip

If you are matching an existing detail, check that you need the A21Z and not the longer A23Z before ordering. They share the same leg widths, but the A23Z has a longer leg and different published load values.

Warranty & Support

Supplementary marketplace data lists a 12-month warranty description for this product.

Tool Nut’s Take

Tool Nut’s Take

Small bracket, useful jobsite insurance for the right connection

The Simpson Strong-Tie A21Z Angle is the kind of connector that earns its keep when a small wood joint needs to be straighter, stronger, and more repeatable than nails alone can deliver.

• Who it’s for: Framers, remodelers, deck builders, maintenance crews, and serious DIYers handling wood-to-wood 90-degree connections.
• Why it stands out: You get a compact 18-gauge framing angle with ZMAX corrosion resistance, which makes more sense for treated lumber and exterior exposure than a basic finish.
• Worth knowing: This is a small connector, not a heavy post-to-beam solution. Also, connector performance depends on using the specified fasteners, so do not treat the hole pattern like a suggestion.

Common Questions

• What is the Simpson Strong-Tie A21Z Angle used for? It is used for fastening wood-to-wood joints at 90 degrees in framing, repairs, and general connector applications.
• What makes the A21Z different from the A21? The A21Z uses Simpson Strong-Tie’s ZMAX coating, which is intended to provide added corrosion resistance for exterior and treated-wood applications.
• What fasteners are used with this framing angle? Supplementary product data lists 10d x 1-1/2 in. nails or #9 x 1-1/2 in. Strong-Drive SD screws, and Simpson specifies using all required fasteners.
• Is this angle approved for treated lumber? Yes. Supplementary Lowe’s data lists the A21Z as ACQ approved.