When material is too thin to tap threads, clinch nuts and rivet nuts are used to help fasten the application. Both rivet nuts and clinch nuts allow for additional components to be attached using these threaded fasteners, and both attach mechanically to the base material. But what’s the difference? Which one is better?
Using a Clinch Nut over a Rivet Nut
Clinch nuts are great. They are smaller, self-clinching, internally threaded nuts that are pressed into the base material. Some of the advantages of using a clinch nut over a rivet nut are:
Can be installed in very thick base material.
There can be almost flush installation on the base material with clinch nut installation. Some small flange rivet nuts or countersunk rivet nuts can make near flush installation, but not as flush as clinch nuts.
There isn’t a specific installation tool for clinch nuts. They can be installed with something like an arbor press, though automation systems are very popular for clinch nut installation.
Can fit different material geometries than rivet nuts.
Using Rivet Nuts over Clinch Nuts
Rivet nuts are also great. Often referred to blind rivet nuts, they are threaded inserts that install on one side of the application to provide a strong attachment point. Unlike clinch nuts, these are installed by pulling the base of the rivet nut and crimping it to one side of the material, instead of being pressed on. Installation requires specific rivet nut tooling to crimp the rivet nut on to the material. Advantages of rivet nuts of clinch nuts are, generally:
Rivet nuts have a wide variety of shapes, sizes, and can even feature floating threads.
Very easy to install with proper tooling.
Stronger thread. Rivet nuts, generally, and especially with hexagonal body, are more resistance to spin-out than clinch nuts.
Cost of standard rivet nuts is similar to the cost of a standard clinch nut.
Comparing and Contrasting Installation of Clinch Nuts and Rivet Nuts
When installing Clinch Nuts, access to both sides of the base material is needed. For Rivet Nuts, installation is only needed with having access to one side of the base material or work piece.
For high volume installations, fastener automation systems are the preferred method to install both clinch nuts and rivet nuts, but some rivet nut hand tools can be used for high volume installation of rivet nuts, including for use on an assembly line. For a manual approach to installing clinch nuts, something as simple as an arbor press can provide installation.
With price between clinch nuts and some standard rivet nuts as fairly similar, factors into determining when to use a clinch nut can be:
Is there access to install using the backside of the work piece?
How much thread strength and spin out is required for the application?
Will installations be performed by an operator or through automation?
The answer to these questions will help determine if a clinch nut or rivet nut will make the best fastener for your application. For suggestions on the best fastener to use for your project, please contact Sherex Fastening Solutions.
There are variety of ways to install fasteners like rivet nuts or clinch nuts into workpieces. Hand tools — manual, hydro-pneumatic, or pneumatic, are popular options and are used in low and high volume assemblies.
Automation is another option. Fastener automation systems usually consists of a robotic arm or robotic station where fasteners are automatically installed into the workpiece. In some cases, this removes the need for a human to be involved, letting the automation system handle the work itself. Sounds great, but let’s take a look at when using these systems make a lot of sense, and the advantages of having an automated system.
Large Quantity Installations
Automated fastening systems are typically used for high volume installations, on an assembly line for example. These systems install fasteners faster than manual assembly, and it might not take much human operation besides initial set up. Some automation systems even have a mobile arm that grabs the work piece and installs the rivet nut or clinch nut. Either way, the cycle time from part installation to part installation on an automated fastening system are faster than installations with spin-pull hand tools, which are also used in high volume installations, by at least a 2 to 3 seconds. Multiply that over the course of an hour and your throughput could increase considerably.
Automation Fastener System with Mobile Arm
24/7 Installations
US manufacturers are BUSY. Demand for everything from cars, to exercise machines, to refrigerators, to furniture is through the roof. Increase in demand means time is money. The quicker things leave the plant, the more money to be made. This is where automation comes in. Automated fastening systems can run 24/7 without the need for humans. Once set up properly, and enough fasteners and materials are in place, the fastening systems can be self-sufficient. As long as there are parts and a conveyor system, the system could run non-stop.
For as intelligent as mankind is, we’re also clumsy. Robots, on the other hand, are precise. Automated fastening systems install parts to the exact force and at the exact location every time. Some systems also come with process monitoring, which can tell if the part has been installed properly based on a variety of factors, including pulling force of the system and material thickness of the application. If an installation is improper, a stop tool function is an option to ensure no more unsatisfactory installations take place which would avoid rework and material waste. This also prevents potentially dozens or hundreds of unsatisfactory installations from taking place.
ROI
This is the most important factor in any decision about automation. What’s the cost? And will I make my money back? It’s no secret that automation is more expensive than a traditional spin-pull, line ready tool like the FLEX-5. But factor in increased quality of installations, increased throughput, and ability for the fastening system to be more efficient and able to run without operators, the return on investment could be substantial over time if you factor in labor costs. Maintenance on automation systems will occur over time, and it might be recommended to have yearly scheduled maintenance on the systems to ensure efficient performance, but during that time there could potentially be no rework, no waste, and outstanding quality at no operator expense.
Sherex has a wide range of fastening installation systems that can satisfy a wide range of high volume rivet nut and clinch nut installations. The Sherex Engineering Team can help determine the best tooling option at your facility, including if automation is an viable option. Contact us to learn more about fastener automation and how it could be a solution at your location.
Deciding on what fastener to use on an assembly takes a lot of time and effort.
First you have to analyze what fastener will provide the proper strength and grip to secure joints, and then combine that with the right tooling to make installations efficient. These processes take a lot of time and effort from engineering to determine the best fit for your product, and that doesn’t even factor in the investment in purchasing fasteners, tooling and calibration units.
So when it comes to the actual installation of the fastener on to the assembly, and after putting in all the work to find the correct product and tooling, the installation has to be perfect. Unfortunately, this isn’t always the case.
Sherex Process Monitoring System analyzes fastener installations
When installing fasteners at a high volume, anything from human error, tooling issues, improper hole sizes or material thickness variations may occur from time to time. These improper installations could lead to bigger problems down the road. Not only could it lead to safety concerns, but could also lead to material waste, re-work, and other expensive delays that cost manufactures valuable time and money.
This is why Process Monitoring is so important. Having a Process Monitoring Installation System in place lets the operator/installer know if their fastener installation is satisfactory or not. With a system that’s configured to the specific part that’s being installed, along with the thickness of the base material it’s being installed into, these systems determine the results of an installation instantaneously. Add in the historical analysis of the installations that are occurring, and installations are driven by quantifiable data, not just by user feel. These systems even support a “stop tool” function to allow operators to analyze or reinstall the part if installation wasn’t satisfactory.
Process Monitoring Systems are required in a number of industries, including automotive manufacturing, and they’re becoming more popular. The ROI on a Process Monitoring System compared to the time and waste of incorrectly installed items, or even potential litigation from an installation that wasn’t perfect, could pay for itself relatively quickly. These systems can be used in low or high volume installations, including on an assembly line.
With installations being so critical to the assembly of any product, the risk of not knowing if an installation is proper is not worth saving a few bucks, especially if a worse case scenario happens, whatever that may be. Process Monitoring Systems combines quality control and efficiency so installers can feel good when the assemblies keep moving down the line.
We all know the advantages of RIV-FLOAT® and what makes it one of the most unique rivet nuts on the market today. But this new video gives greater insight of how it works.
Take a look at the video below. Notice how the how the floating rivet nut installs like any other rivet nut, but when tightening the bolt to secure the joint, there’s a little play that allows the bolt to be installed “out of perpendicular.” This is a big advantage and very convenient for assemblers.
There are also benefits besides speed and convenience of assembly, like knowing there won’t be cross-threading, and spin-out performance is improved since the floating thread helps align the screw angle during assembly.
Watch the video and see how RIV-FLOAT can make assemblies more efficient and improve the performance of applications.
When most people think of rivet nuts, they think of little, round body fasteners that are easy to install and have a wide variety of uses.
In reality, we should begin to think of them in hexagonal form. Hex body rivet nuts are amongst the strongest, best-performing rivet nuts on the market today.
Hex body rivet nuts come in the same material as round body (aluminum, steel, stainless steel, etc.), they can have a large flange or small flange, and, like their round-body counterparts, can possess special features such as a mechanical lock to keep joints secure in high-vibration environments, or a watertight gasket to keep dirt, water, dust, or other potential corrosives from degrading the joint over time.
Most importantly, hex body rivet nuts out perform their round body brothers in just about every performance metric available. Spin-out, torque out, push out and pull out. Look at the graphic below to see the overwhelming spin-out performance boost offered when switching to a half-hex or full-hex rivet nut body style.The hex body rivet nut is almost 10 times stronger than a typical, knurled round body rivet nut when installed in the same material. Due to their larger cross-sectional areas, full-hex rivet nut body styles also have increased thread performance as well as enhanced pull-out/push-out resistances when compared to their round-body and half-hex counterparts.
Testing hex body rivet nuts in 1/4-inch thick steel for an agriculture equipment manufacturer
Although hex body rivet nuts can be installed in any material, steel or harder materials will provide the best mechanical properties for improved performance. Just keep in mind the potential for galvanic corrosion when choosing certain materials for your rivet nut versus the base material it’s installing in.
The only caveat with hex-body style rivet nuts? You need a hex hole to install them with. For many manufacturers, making hex holes quickly and reliably (or, sometimes, even at all) can be a complicated task and the main barrier of entry, but it’s a process that in the long run will make that manufacturer’s products perform better when using rivet nuts. Many manufacturers are making the switch, knowing the performance will last.
Half-hex body rivet nuts are available as well, but they too need to be installed in hex holes. The prevailing advice is to go with full hex due to the previously-mentioned structural benefits provided by the larger cross sectional area. However, half-hex rivet nuts maintain many of the enhanced spin-out benefits at a lighter weight and at a lower cost.
Sherex’s FHL, FHK Series and large style LRGH Series rivet nuts are becoming more and more popular and used by many manufactures in automotive, heavy truck, and construction and agriculture equipment industries.
It’s really quite simple, if you can produce a hex hole, you should be using a hex body rivet nut. For more information about hex body rivet nuts and using them in your applications, contact us!
Rivet nuts have a wide variety of uses. They are used to assemble furniture, automobiles, refrigerators, exercise equipment and everything in between.
But what about huge pieces of equipment, like large construction and agriculture equipment? Could a little rivet nut handle the rigors of heavy vibration and rigorous use that construction workers and farmers demand out of their large investments? Short answer is yes. The rivet nuts that are used in those pieces of equipment are just bigger and stronger.
Lots of balers, tractors, dump trucks, and other enormous earth movers use large size, high strength rivet nuts in their assemblies. These rivet nuts provide the strength needed to handle the rigors of these giant machines. In our testing, Sherex’s 5/8-11 LRGH Full Hex Rivet Nuts had a pull out strength over 30,000 pounds of force, spin out was greater than 157 ft-lb and torque out greater than 250 ft-lb. To give an example of how strong the torque out is, a Grade 5 bolt recommended assembly torque is 120 ft-lb.
LRGH Series — This Large Size, Full Hex Rivet Nut is amongst the strongest rivet nut available.
Large size rivet nuts come in thread sizes as large as 3/4-inch and M16 and can come in both round body style and hex style. The large size, hex body style rivet nut is amongst the best performing rivet nut on the market today, as the hex body provide superior spin-out performance to any round body rivet nut.
To install these large size, high strength rivet nuts, you need a large size, high strength tool. Sherex’s FLEX-18 delivers up to 18,000 pounds of force to install these rivet nuts on the assembly line.
3D Models of Large Size, High Strength Rivet Nuts Available!
3D Models of Sherex’s Large Size, High Strength rivet nuts are now available for download on Sherex.com and Traceparts.com. For those interested applying large size rivet nuts to your project, please contact us to talk to our engineers.
With an easy to use sort function, find the correct rivet nut based on thread size and material thickness, click on the 3D icon in the table, then download your 3D rivet nut in just seconds.
The 3D widget allows users to use the mouse to drag, turn the model, and zoom in and out using the scroll wheel.
There are over 50 different file type prints are available for download, including including SOLIDWORKS, AutoCAD, and PDFs, with each 3D model. Design engineers are encouraged to download our installed models for better design capabilities in their projects.
This project with ThomasNet and Traceparts integrates the 3D models of installed versions of rivet nuts that are available on TraceParts onto Sherex’s website for a better user experience for those looking for quality rivet nuts.
Find the right style and size of your rivet nut faster. Check it out!
For installing rivet nuts into flat materials, the solution is usually rather simple when it comes to geometry. It usually just comes down to making sure there’s sufficient clearance for installation and the right hole size to properly fit the rivet nut. Since the material is flat, the only thing to worry about is ensuring the rivet nut is suitable for use with the thickness of that material.
With curved materials, the options may be narrowed down, and a solution may become more complex.
Installing Rivet Nuts in Curved Surfaces
The options depend specifically on the curvature of the material. Since the entire circumference of a rivet nut collapses onto the material, the geometry of the rivet nut’s crimping bubble will possess the same curvature as the material it’s mating to.
If the base thickness is in the middle of a rivet nut’s grip range, the curvature may not have a significant effect, as the grip range would cover all of the effective thicknesses that rivet nut is crimping onto. However, if a rivet nut is installing into a base thickness toward the upper edge of its grip range, it may have trouble properly installing if the curvature is at all substantial. To account for this, there are two main options.
Material thickness plays a big role in determining whether a rivet nut can be installed in a curved surface
The first option, sometimes preferable for thicker curved material, would be a swaging-style rivet nut. These rivet nuts expand into the installation pane rather than crimp onto it, and thus only have to meet a minimum thickness requirement. Swaging styles are recommended for high (or variable) thickness applications where high joint strength is not an option.
For improved spin-out, pull-out, and torque-out performance, pre-bulbed and slotted rivet nut styles are the recommended option for variable thicknesses. These rivet nuts are typically suitable for large thicknesses, but also a wide range of them. This is because the slots of the rivet nut fold over to collapse onto the material, rather than a significantly smaller counterbore region found in other body styles.
Typical round body rivet nut in curved material
If installing tin to curved surfaces and have questions, feel free to reach out to Sherex’s engineering team with application details and performance requirements. Whether for standard round or hex body rivet nuts, swaging, slotted, or pre-bulbed, Sherex will help guide to users to a recommendation we have the tools to determine the best solution for you.
After reading Why Rivet Nuts?, you may come away with, well that’s good, but what’s a rivet nut stud?
Rivet nut studs are simply rivet nuts with an already outward protruding stud installed in the rivet nut. Instead of threading the bolt into the rivet nut, you thread your attachment on to the bolt and you would attach a nut to tighten down the attachment.
Sherex Rivet Nut Studs
They work the same way as a blind rivet nut, are installed in a similar way, and already have the stud installed. This saves installers the step of putting in the through bolt. Also, when putting an assembly together, it can be beneficial to have something that gets hung on the stud before getting tightened down. This gives the operator something to take the weight off the component before installing the nut over the stud.
Like most blind rivet nuts, rivet nut studs are great replacements for weld nuts when you need a blindly installed, outward-protruding stud for your joint. They are also only needed to be installed in one side of the work piece, where access to the backside is not possible.
Rivet nut studs can come in a variety of sizes and shapes. Round body, hex body, wedge head, knurls – anything a typical rivet nut can be made into and rivet nut stud can. Rivet nut studs are very customizable. Another thing to consider is the stud. How much thread or stud length will you need for the application? Rivet nut studs can be made to a specific length for the application.
The performance of rivet nut studs vs. a typical rivet nut is very similar, although harder material like steel might yield better performance results than softer material. In general, the performance of spin-out or pull-through of a rivet nut stud compared to a typical rivet nut is negligible if all things are equal.
Rivet Nut Stud Application Use
There are a number of different applications a rivet nut could be used for:
Wire harnessing on a Truck Frame
Any applications where a rivet nut stud will be used as a hanging point on a centering pin
Locating or guide pin
Can replace any weld nut application
Automotive applications, like spoiler installations, installed into castings, roof racks
Agriculture applications
Heavy Truck applications
Rivet Nut Stud Application on Automotive Casting
Rivet nut studs are typically more expensive than a rivet nuts, but remember, the cost of the stud or bolt is also considered into the higher price. When you factor a rivet nut plus a bolt/stud, it’s roughly the same amount per part ($rivet nut stud = $rivet nut + $stud/bolt). Another thing to consider is the potential in time saving, or even ease of assembly for assemblers and installers. Rivet nut studs could very well be a more productive fastener depending on the application, saving money by being able to assemble more products faster.
Rivet nut studs are a great option and should be considered any time you have an application that needs a rivet nut and weigh out the options if it makes sense to use one. If you’d like to speak to one of Sherex’s application engineers to see if an application is worthy of a rivet nut stud, contact us!
There are dozens of different styles of rivet nuts manufacturers can choose from when deciding on a fastening solution to help improve their assembly. While the material, coating, size, body style are all important, how the rivet nut performs under strenuous conditions is often times what matters the most.
Performance testing of rivet nuts is extremely important. It helps validate how the rivet nut will perform under an array of conditions to give manufactures and assemblers assurance that under that same kind of stress in their own design application, their joint will be able to hold up to any expected loading condition.
Here are some of the ways Sherex conducts rivet nut performance testing.
Pull-Out Testing
Pull-out failure occurs when threads are pulled from the rivet nut (ultimate thread strength), or when the base material is distorted and the rivet nut (either partially or entirely) pulls through the base material. Sometimes this happens with the hole size is too big for the rivet nut or when the force applied to the joint is higher than anticipated, causing the rivet nut to pull right through the hole.
Using a tensile machine to pull the rivet nut through the hole
This is tested by assembling our joint into a tensile machine. Tensile load on the joint is increased until the integrity of the crimp fails, whether it be due to material deformation or due to severing of the crimping bubble from the flange of the rivet nut.
Spin-Out Testing
Spin-out is the amount of torque required to make a rivet nut spin in the hole it was installed in. This happens when the bolt cross-threads into the rivet nut, causing it to spin. It can also occur when excessive corrosion causes the bolt to bind in the nut.
What it will take for the rivet nut to spin in the hole?
This is tested by assembling a test bolt into the shank end of the rivet nut. Torque is increased until the integrity of the crimp fails and the rivet nut starts to spin in the material. Failure torque recorded is the maximum torque reached before the rivet nut starts to spin.
Torque-Out Testing
This is the torque required to strip threads out of the rivet nut. This method of testing sandwiches the head of the rivet nut between the non-rotational mating part and parent or base panel.
Spin-out is not a factor because tightening the bolt on the non-rotating part holds the rivet nut in place and prevents it from spinning.
Torque the bolt on the flange side of the rivet nut until the bolt, rivet nut, or base material is compromised
This is tested by assembling a test bolt into the flange side of the rivet nut, with the flange supported entirely by a hardened test plate. Torque is increased until the integrity of the joint fails, whether it be due to the bolt snapping inside the rivet nut or due to the threads of the rivet nut stripping. Failure torque recorded is the maximum torque reached before thread failure occurs.
Assembly Torque / Clamp Load
Sherex gives recommendations for the assembly torque to achieve recommended clamp load in our catalog to give the recommended torque for assembling a rivet nut joint using any Sherex-manufactured rivet nut. Testing is for this is important, because different joint configurations will produce different clamp load levels.
Assembly torque is calculated as a ratio of proof load, which designates thread strength per SAE J995 for unified (UNC/UNF) internal thread sizes and ISO 898-2 for metric sizes. This is our recommendation for Sherex-manufactured parts meant to meet Grade 5/Class 8 thread strength specifications. All torques designated represent recommendations for assembly from the flange side with the flange entirely supported.
All failure loads, torques, and assembly recommendations are heavily application-dependent, and any recommendations found in the catalog or results from different applications should only be used as a reference.
For any questions on testing or any parts that require a higher grade or property class designation, please contact us!
