Snap-in Cage Nuts

Snap-in Cage Nuts, commonly called Cage Nuts, Rack Nuts, or Server Rack Nuts, are captive threaded fasteners used where a threaded hole is required in a sheet-metal panel or rack rail. The nut is retained inside a spring-steel cage, allowing the assembly to clip into a square mounting hole while leaving the threaded nut slightly movable for alignment during screw installation. This makes the fastener particularly useful where access to the rear side of the panel is limited.

Cage nuts are especially common in 19-inch server racks, network cabinets, equipment racks, control cabinets, electrical enclosures, and sheet-metal assemblies. They allow equipment, panels, shelves, brackets, and other components to be secured without tapping threads directly into relatively thin sheet material. The floating action of the captive nut can also compensate for minor positional differences between the mounting hole and the equipment being installed.

Instead, commercially available designs use different metric and imperial thread sizes and may be manufactured to application-specific dimensional requirements. Metric versions such as M4, M5, M6, M8, and M10 are common, while imperial versions including 10-32 and 12-24 are widely used in rack equipment. Rack systems themselves may follow standards such as IEC 60297, but this should not be confused with a dedicated Cage Nut product standard.

For industrial purchasing, the important selection factors are thread size, cage configuration, mounting-hole dimensions, panel thickness compatibility, nut material, cage material, and surface finish. Cage Nuts can be supplied in carbon steel and stainless steel, with finishes such as zinc plating, nickel plating, or plain surfaces depending on the application.