When most people think of hex nuts, they envision a six-sided fastener with internal threading. After all, the term hex refers to objects with six sides, so conventional wisdom may lead you to believe that all hex nuts have six sides. While conventional hex nuts do, in fact, have six sides, double hex nuts feature a different design.
What Are Double Hex Nuts?
Double hex nuts are characterized by a 12-sided design. They are known as double hex nuts because they essentially feature two overlapping hexagons. A second hexagon is placed over the existing nut’s existing hexagon, resulting in a 12-sided design.
With their 12-sided design, double hex nuts offer more engagement points for wrenches. Nuts are typically tightened and loosened using a wrench. In confined spaces, however, you may struggle to fit a wrench around the nut. Double hex nuts offer a solution. They offer twice as many engagement points as traditional hex nuts, making it easier to reposition wrenches around them.
How Double Hex Nuts Work
Double hex nuts work like most other nuts by creating a clamping force. As you tighten a double hex nut onto the end of a bolt, it will create a clamping force. This force will hold the assembled parts together.
You can loosen and remove double hex nuts using a wrench. Double hex nuts are temporary or semi-temporary fasteners. Placing a wrench around a double hex nut and turning it counterclockwise will loosen it from the bolt.
A standard hex nut requires the wrench rotate 60 degrees. A double hex nut, on the other hand, cuts the required rotation angle in half, making them ideal for tight spaces.
Common Features of Double Hex Nuts
You can find double hex nuts with built-in washers. They feature a wide, flat base that sits directly below the 12-sided design. This built-in washer helps to distribute the bolt’s load across a larger surface area, thereby protecting the assembled parts from load-related damage.
Many double hex nuts feature a prevailing torque locking mechanism. These specialized nuts are able to resist unwanted loosening caused by vibrations or thermal cycling. Prevailing torque nuts feature a collar or threads that, during installation, deform to create friction.
Another common feature of double hex nuts is a corrosion-resistant finish, such as zinc or cadmium. They are often used in environments where humidity or moisture is a concern. A corrosion-resistant finish acts as a protective barrier to shield the nut’s underlying metal from direct exposure to moisture.
