Stainless steel wedge anchors are designed for use in moist, wet environments. When the application is indoors or in a dry environment, use the standard zinc plated carbon steel wedge anchors. "Wedge anchor" is the generic name for a specific type of anchor used to fasten an item to solid concrete. A stainless steel wedge anchor is manufactured from two different types of stainless steel.
Grade 303/304, commonly called 18/8 stainless steel wedge anchors, are excellent for use in a wide range of atmospheric environments. This type of stainless steel with its chromium-nickel and low carbon provides ease of manufacturing and cleaning. It is commonly used in wet environments or when it will be submerged in water that is free of chemicals. The 316 stainless steel has superior corrosion resistance when exposed to many types of chemicals corrodents, such as sea water, brine or chlorine, as compared to the 303/304 and other chromium-nickel steels.
The 316 stainless steel wedge anchor costs more than the 303/304 stainless steel wedge anchors because the steel itself cost more and it takes more time and machining to manufacture,
Many manufacturers do not make all diameters of wedge anchor in stainless steel. Most companies do not carry the 5/16”, 7/8” and 1-1/4’ in stainless steel. Concrete Fastening Systems, Inc. has available all diameters for both 303/304 and 316 stainless steel and nine diameters to choose from 1/4”, 5/16”, 3/8”, 1/2”, 5/8”, 3/4”, 7/8”, 1” and 1-1/4. The diameter of wedge anchor chosen for any specific job is determined by the weight of the object being fastened, the diameter of the holes in the item being attached, or is specified by an engineer.
Each diameter of stainless steel wedge anchor must be embedded into the concrete a minimum distance for holding power. This minimum depth of embedment will ensure minimum holding values. Deeper embedment beyond minimum embedment may increase holding values but may also create problems. A problem that may occur at deeper embedment is running into rebar embedded in the concrete. Another problem at embedment of 8” to 12” is difficulty drilling the hole straight enough for the anchor to be fully inserted.
The chart below shows the minimum embedment depth for only those wedge anchors sold by Concrete Fastening Systems™, Inc.
|Anchor Diameter||Minimum Embedment|
Each diameter of stainless steel wedge anchor is available in a number of different lengths. Most manufacturers do not make all lengths for both types of stainless steel. Concrete Fastening Systems, Inc. has all lengths for both types as well as the ability to manufacture special lengths if needed. The minimum length of anchor required for any specific job is determined by adding the thickness of the material being fastened to the minimum embedment plus space for the nut and washer. The length of a stainless steel wedge anchor is measured as an overall length from one end to the other.
The length of threads on the stainless steel wedge anchors can vary based on the diameter and length of the anchor being used. The amount of threads should be sufficient to allow for the nut and washer to be threaded once the anchor is installed in the concrete. To install the stainless steel wedge anchor properly, 3 to 4 threads must be below the surface of the concrete or item being attached in order to provide a draw on to ensure proper expansion.
Each diameter and length of stainless steel wedge anchor is packaged with the correct number and size of nut and washer. The quantity in each box differs based on the diameter and length as well as the manufacturer.
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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.