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14 gauge sheet metal is difficult to drill into with our self-drilling eye lag screws. There are several variables which can affect the ability of the screw to set correctly.

Principally, the variables are thickness of the metal, tensile strength of the metal and skill of the installer.

The 750 SD was designed to be installed in 18 gauge sheet metal (0.0478” thick). This is the thickness of most of the metal decking that the 750 SD is installed in.

During installation, the 750 SD threads into the sheet metal. The core of the threads is about 0.190” in diameter. This core is forced into a 0.165” hole made by the drill point.

In other words, the sheet metal is forced to expand beyond the size of the hole drilled by the drill point.

The 750 SD will work with 16 Gauge (0.0598” thick) if the screw is carefully installed. But please note, if too much force is used, the screw could snap or strip out in the deck.

I really do not see how the 750 SD could penetrate and thread into anything thicker than 16 gauge. However, the only way to be certain is to actually attempt an installation.

Perhaps the ELDX self-drilling screw would be a better choice, as it is designed for thicker material and has a larger diameter drill point. We know that the ELDX works well in 12 gauge (0.1046” thick) material. Here again, the skill of the installer is an important variable as the ELDX could “strip out” if the installer isn’t careful.

Many installers use the 750 SD in purlin or red iron.

However, they cannot fully set the screw all the way to the collar in red iron or purlin because the metal has a high tensile strength, even if the metal it is relatively thin.

ICC requires that our self-drilling screws have at least 3 threads protruding through the steel deck panel to be considered properly installed.

Perhaps a better fastener in this situation would be a spring steel clip such as the ADOC14 or VOH14 as these do not require penetration into the purlin structure.