Below is a listing as well as expansion shield info for the different expansion shields’ features and benefits, with links to both technical information and product information for various types of these ingenious anchors. Concrete Fastening Systems ™, Inc. naturally sells all these varieties, and more!
The drop-in anchor is the newest type of expansion shield and is designed for use in solid concrete only and cannot be used in brick or block. The drop-in anchor comes in five diameters of 1/4”, 3/8’, 1/2”, 5/8” and 3/4”. It requires the use of a setting tool for expansion of the anchor in the concrete. The drop-in anchor is manufactured in zinc plated carbon steel, 304 stainless steel, and 316 stainless steel. Drop-in anchors have excellent holding values and may be used in overhead applications.
The machine screw anchor was designed many years ago and works well in all masonry materials such as brick, block or concrete. The machine screw anchor comes in nine diameters of #6, #8, #10, 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. All sizes require the use of a setting tool to expand the anchor in the base material. The machine screw anchor is made of two parts: the inner threaded part made from die cast Zamac material and the outer anchor body made of a rust-resistant alloy. The machine screw anchor is versatile and has excellent holding values.
The single expansion anchor works well in hard dense base materials such as concrete, brick or block. The expansion occurs in one area of the anchor body. It is very important to make sure the anchor’s expansion area is in the solid part of the masonry. The single expansion anchor come is six diameters 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. It is expanded by inserting a machine threaded bolt. The threads in the single expansion anchor are national coarse threads, therefore the bolt used must have threads that are national coarse threads. The single expansion anchor is made up of two parts: the anchor body and the expansion nut. It comes pre-assembled and ready to use.
The double expansion anchor works well in the suspect base material because the expansion occurs along the entire length of the anchor body, which provides holding values even in the softest base materials. The double expansion anchor is manufactured in six diameters of 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. All are expanded by inserting a machine threaded bolt. The anchor has two expanding nuts (one on each end) which ensure consistency and even expansion along the entire anchor body. The double expansion anchor comes fully assembled with two wire expanding rings holding the entire anchor together.
The lag shield anchors are manufactured in a short version and a long version. The short version is used in hard dense base materials and the long version is used in an application where the base material is softer. Inserting a lag screw expands the lag shield; a machine bolt will not work. Both the long and short lag shield come six diameters of 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. Lag shields are made from a Zamac material, are cast in two pieces, and are pre-assembled into a single unit.
As with any anchoring project, it is important to keep safety in mind and follow instructions carefully. Always remember to wear safety goggles, handle all tools with extra care and follow all technical specifications. This article is meant to serve only as a basic explanation of concrete fasteners. Always refer to manufacturer's instructions or consult a contracting expert during any anchoring project.