Rivet nut installation upgrade#

“If you’re fastening soft plastic, a spin-pull tool might be better,” says Lanni. It works the same as the spin-pull tool, but instead of pulling to a set distance, it pulls to a set pressure. Once the fastener is set, the air motor re-engages to back the mandrel out of the nut.Ī third option is the “pull-to-pressure” tool. When the fastener is inserted into the workpiece, hydropneumatic pressure is applied to pull back the mandrel a set distance. As with the spin-spin tool, an air motor threads the mandrel into the nut.

Rivet nut installation upgrade#

Thus, rivet nuts can be fitted at any stage in the production process.Īn upgrade from the spin-spin tool is the “spin-pull” tool. No additional finishing is required after setting, even with coated or painted components. Once the rivet nut is clinched securely in place, the mandrel spins in the opposite direction, unthreading itself from the nut and leaving the fastener’s internal threads intact. The bulge presses against the rear of the panel, creating a clamping force that tightly grips the sheet. When the tool is actuated, the mandrel spins rapidly and powerfully, pulling the threaded portion of the rivet nut’s shank toward the blind side of the workpiece and forming a bulge around the unthreaded portion. The fastener is then inserted into a hole in the workpiece. The fastener is threaded onto a mandrel at the end of the tool. The simplest power tool for installing rivet nuts is the pneumatic “spin-spin” tool. They can also be mounted to six-axis robots. The latter can be handheld or mounted to a linear actuator for fully or semiautomatic operation. The former are similar to tools for installing blind rivets. Rivet nuts can be installed with hand tools or, more commonly, power tools. The closed end thus prevents the ingress of water and dust into the interior of the assembly. The latter are ideal for applications, such as attachment points on vehicle exteriors, in which the mating screw will not necessarily be present. Rivet nuts are also offered in open- and closed-end versions. For some manufacturers…it’s cheaper to make a round hole than a hex-shaped hole.” “The downside of a hex-shaped fastener is that it requires a hex-shaped hole.

“With a hex-shaped fastener, you don’t have that issue. “If they’re not set just right, round rivet nuts can spin in the hole at high torque levels,” explains Lanni. Such variations are all designed to do one thing: keep the fastener from turning in the hole, particularly in softer materials, such as aluminum and plastic. The standard rivet nut is cylindrical with a smooth surface, but variations include splined, square and hexagonal bodies.

Rivet nuts also come in many body styles. The wedges aren’t going to be very effective on steel parts.” “However, rivet nuts are annealed, so they’re relatively soft. “The wedge head is great for soft materials like plastic, fiberglass and aluminum,” says Kull. Wedges or knurls underneath the head are designed to bite into the mating material and prevent the fastener from turning in the hole. Countersunk and low-profile heads ensure flush or near-flush installation. A thick flange can act as a spacer and provide some extra push-out strength. It’s also possible to apply a sealant beneath the flange for weatherproof applications. This reinforces the hole and prevents push-through. A wide front-side flange provides a large load-bearing surface. Rivet nuts are available with a variety of head styles. A 1.45-inch long rivet nut has a grip range of 0.35 to 0.5 inch. For example, a 0.42-inch long SpinTite rivet nut from PennEngineering offers a grip range of 0.02 to 0.08 inch. A single fastener size can typically accommodate a wide grip range.