Plus Nuts: A Unique Style of Rivet Nuts
The Plus Nut, also known as PLUSNUTยฎ, or Versa-Nutยฎ, is a special type of rivet nut with unique properties that set it apart from standard rivet nuts. Developed after the original rivet nut, Plus Nuts were designed to offer reliable fastening performance in applications where precision and durability are critical.
With the widest material grip range among blind threaded inserts, Plus Nuts can reduce the number of fasteners needed in an assembly. They also boast unparalleled pull-out strength in thin sheet metals, soft materials, plastics, composites, and fibreglass. During installation, their slotted body splits into four legs, creating a broad load-bearing surface on the backside of the parent material. This unique feature has led to its occasional reference as โsplit rivet nutsโ.
Regular Plus Nuts vs. Pre-Bulbed Plus Nuts
Plus Nuts come in two main styles: the regular straight-body and the pre-bulbed. A regular Plus Nut has a straight cylindrical body, while a pre-bulbed Plus Nut has a slight bulge midway along the body.
The pre-bulbed design makes installation easier, providing a user-friendly experience for production work where efficiency is paramount, as well as for DIY enthusiasts or low-volume installers. Both types, when installed correctly, offer excellent durability and resistance to spin-out.
| Feature | Pre-Bulbedย | Regular (Straight-Body) |
| Body Shape | Pre-formed bulge mid-body | Straight cylindrical body |
| Slots | Longitudinal slots to guide expansion | Longitudinal slots to guide expansion |
| Flange | Thin step under flange for better alignment with hole size | No step under the flange - allows better attachment, more friendly on softer materials (e.g., plastic) |
| Hole Size | Slightly larger than the body diameter to allow the bulged section to insert | Matches body diameter |
| Bulb Formation | Forms more easily/faster due to the pre-shaped body | Forms a bulb only upon installation |
| Installation Ease | User-friendly, requires less tool force, quicker setting | Needs a long stroke tool to initiate and control bulbing |
| Installation Tool | Compatible with spin-spin, spin-pull, ratchet-style hand tool, or even DIY tool | CAN NOT use spin-spin tool *; requires more effort with hand tools |
*Using a spin-spin tool on straight-body Plus Nuts can twist the body and result in incorrect installation. The image below shows the result of installing a straight-body Plus Nut with a spin-spin tool:
Why are Plus Nuts Different from Standard Rivet Nuts?
While Plus Nuts are a type of rivet nut, they should not be confused with standard rivet nuts. They require tools with longer strokes and longer mandrels due to their longer body and unique bulbing properties. Using a standard rivet nut tool may result in inconsistent installation and reduced performance.
Recommended installation tools from RivetLab include:
- TA-800 series spin-spin air rivet nut tool - suitable for installing pre-bulbed Plus Nuts
- RT-512 Hand Ratchet Rivnut Tool with long mandrels - works with both types
Why not DIY tools?
DIY methods for installing Plus Nuts might work for small, one-off projects, but theyโre not suited for serious or repeated use. Homemade tools like wrenches lack precision, wear out quickly, and often damage the fastener โ leading to poor installs, rework and corrosion risks. Professional tools are built from hardened metals to deliver consistent, reliable, and damage-free installations every time. While DIY setups may seem cheaper upfront, proper tools ensure safety, durability, and long-term value.
Key Considerations for Plus Nut Installation
- Choose the appropriate fastener material to prevent galvanic reaction
- Measure the material thickness and select the correct grip range of plus nuts.
- Use the recommended tool for the chosen plus nut style.
- Refer to the datasheet and drill the correct hole size as specified by the manufacturer (note the difference between pre-bulbed and straight-body styles).
- Run tests before moving into production.
Installing a plus nut into an oversized hole, or using one not suited to the material thickness, can result in spin-out or premature failure. Following the correct installation parameters ensures reliable fastening every time.
Not sure about the setup, tool selection, or which Plus Nut style to use? Call us โ weโre here to help.
