The Keep-Nut insert from Chemical Concepts is an innovative fastener for high-strength anchoring in very hard substrates such as natural stone, composites and hard plastics, where traditional fastening methods are often difficult or impractical. To install the anchors, a hole is drilled to a specified depth and diameter. The anchor is then hammered into place using a rubber mallet and the insert is ready for use. The holding power comes from rows of flexible metal spines that compressed as the anchor is inserted. In use, these metal spines apply force radially along the walls of the hole, achieving tensile strength levels of 250 to 1,000 pounds per fastener, depending on the model used. The anchor is made of stainless steel so it is suitable for use in both interior and exterior applications.

The Keep-Nut is available in a variety of different models for different applications and materials. The first consideration is the thickness of a panel. One advantage of the Keep-Nut is that it can be used in panels of a variety of thicknesses, including fairly thin panels down to 5.5 mm (< 1.4”). If using thin materials, select the variety with the appropriate minimum panel thickness. If using thicker materials make sure to select a variety that will provide the desired strength rating.

Another consideration is bolt and screw selection. The best way to fasten your hardware to the Keep-Nut insert is with threaded rod and hex nuts. The use of threaded rod, as opposed to a screw, is preferred as it allows you fully tighten your hardware to your substrate regardless of the thickness of your hardware. If a screw is preferred, you must be careful to source screws of the correct length. The trick is to make sure your screw length does not exceed the thickness of your hardware plus the thread depth of the anchor.