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Double Expansion Anchor FAQ

What is a double expansion anchor?

Purchase Double Expansion Anchors

A double expansion anchor is a fastener for light duty to medium duty use.

When should I use one?

This anchor should be used when installing an item into softer material, or a material whose strength is suspect.

How does it work?

As a bolt is threaded into the double expansion anchor, the expansion nuts move inward to expand the anchor body against the base material. It expands along the entire length of the anchor, which results in excellent holding values.

What materials are used to make this anchor?

The anchor body of is made from a die cast alloy called Zamac, which is rust resistant and extremely durable.

What sizes are available?

Double expansion anchors come in six diameters: 1/4”, 5/16”, 3/8”, 1/2”, 5/8”, and 3/4”.

What size bolt do I use in this anchor?

The length of the bolt depends on the thickness of the material being fastened, the depth of embedment of the anchor, and space for any washers that may be used. The diameter of the bolt to use is equal to the designated diameter of the expansion anchor being installed.

How many pieces make up the anchor?

It is made up of six parts that are assembled and ready for installation. The parts of this anchor are: two halves of the anchor body, one threaded expansion nut, one non-threaded expansion nut, and two spring steel rings.

What is the difference between the single expansion anchor and the double expansion anchor?

The single expansion anchor has a single expansion nut and expands at one end. The double expansion anchor has two expansion nuts and expands the entire length of the anchor.

How do I install one?

It’s easy to install. Drill the hole, insert the anchor, and set it. For more detailed installation instructions, visit the Tips & Tricks page.

Do I need a setting tool to install an expansion anchor?

No. You don’t need to use a setting tool to set the anchor in the base material.

Can I install these anchors below the surface of the concrete?

Yes. Although most of the time these anchors are installed flush with the surface, deeper embedment will increase the holding strength but will also require a longer length bolt.

How close to an edge of the concrete can I install one?

It must be installed at a minimum distance of five anchor diameters away from an unsupported edge to ensure minimum holding values.

Are double expansion anchors available in 316 stainless steel?

No, these anchors are not available in 316 stainless steel. They are only manufactured from the die cast zinc alloy called Zamac.

Can I get these anchors in hot dipped galvanized?

No, they are not available in hot-dipped galvanized. They are all made from a non-rusting, durable die-cast zinc alloy called Zamac.