A panel nut is a fastener designed specifically for securing small threaded components such as switches, potentiometers, and lamps on the surface of panels and enclosures. This kind of nut is typically of a very low profile with a large hole to overall diameter ratio. Panel nuts may be of conventional hex design for tool fastening or have a round, knurled outer surface for hand fastening. These fasteners are not intended for high torque applications and are often used with spring or lock washers to prevent loosening and component movement. Common panel nut materials include nickel finished brass, nylon, and stainless steel.
Through-panel mounted electrical and audio components such as small toggle and push switches, light emitting diodes (LEDs), and indicator lamps, jack plug sockets and potentiometers are usually equipped with a threaded shoulder/nut arrangement for locking purposes. Typically used on vehicle dashboards, audio equipment, and circuit enclosures, these components are mounted through a hole in the surface of the panel or enclosure with the component connections on the inside and the locking nut on the outside. This locking nut is known as a panel nut and, due to typical design restraints in these sorts of applications, needs to be of a very specific design.
Most of these components feature a threaded shoulder which is often not much longer than the thickness of the typical panel or enclosure wall. This does not leave a lot of thread exposed to accept the locking nut. This requires the panel nut to be of a low profile design to allow for complete thread penetration while still having enough room to include a washer. For this reason, most panel nuts feature an average height of approximately 0.11 inch (2.8 mm) which is a lot thinner than most fasteners.
In many cases, through-panel components are stacked in close proximity to others which also places space constraints on the type of nut used to lock them in place. This means that most panel nut designs feature a very large hole to overall diameter ratio to keep the nut as narrow as possible. An average panel nut will feature a hole diameter of 0.31 inch (7.8 mm) and an overall diameter of only 0.44 inch (11.2 mm). This leaves approximately 1/10 of an inch of “meat” around the outside of the hole, thereby giving the panel nut a very small footprint.
The svelte design of panel nuts means they are not designed to exert a lot of torque and are only meant to secure the component under light pressure. Due to the lack of tightening force applied to these fasteners they are typically used with a spring or lock washer to prevent them from working loose. To this end, these nuts may be hex shaped for wrench tightening or rounded with a knurled surface for finger tightening. Panel nuts make up, for the most part, part of the visual appeal of any installation and are often designed with some decorative finishing such as gloss plating and domed profiles. Common materials used in the manufacture of panel nuts include nickel plated brass, zinc plated steel, nylon, and stainless steel.