Category Archive: Rivet Nuts
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.
You can now download installed versions of our rivet nuts right on Sherex.com.
Sherex Fastening Solutions has over 1,500 3D models of its rivet nuts available for download, including our best performing full hexagonal rivet nut lines, FHL and FHK Series. These 3D Models add to the 3D Models of our TEC Series Washers.
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!
By Frank Genovese
Sherex Applications Engineer
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 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 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.
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!
The Sherex Fastener Fix blog is supposed to be an unbiased, informative, technical and thoughtful conversation on all things fasteners. But once in a while we have to toot our own horn.
Sherex’s patented RIV-FLOAT® rivet nut is truly great. It allows for greater ease of assembly because fastening can occur when the through bolt is off-center.
How does this happen? There’s a .02-inch radial floating nut inside the rivet nut, which allows the bolt going through the rivet nut to be a slightly off-center while pulling the attachments together. Think of when you’re assembling a piece of furniture and you’re trying to get the final attachment holes to line up exactly for your bolt or screw. It can be a pain! With a RIV-FLOAT installed in base attachment, there can be a little play while joining the attachments together with a bolt or screw. And since RIV-FLOAT is a rivet nut, there is no need to attach a nut to the backside.
>>Check out the RIV-FLOAT video on our YouTube Page
RIV-FLOAT development started in 2007. An aerospace customer had an application that required floating threads. The concept was worked on by engineering, and from there it went from drawings to life and eventually a patent.
“The idea came from a customer specific request,” Sherex president Adam Pratt recalled, “but we thought the idea had promise for other markets so we developed the product.”
Other markets include automotive, construction and agriculture equipment, and general industry applications. Applications in these industries are wide ranging. RIV-FLOAT has been used for enclosures for mounting large door panels and in difficult fastening locations where the drive angle can’t get square to the base material.
“RIV-FLOAT can improve ergonomics and improve safety,” Pratt said. “RIV-FLOAT gives customers that adjustment they need to easily assemble these applications.”
When it comes to performance, RIV-FLOAT actually performs better than most standard round body rivet nuts. RIV-FLOAT’s size is a little bigger, which helps. Also, spin-out performance is improved too since the internal threads of the RIV-FLOAT help align the screw angle of the bolt during assembly.
“This dramatically reduces the cross-threading risk in the application and aids in speeding up assembly,” Pratt said.
Overall, RIV-FLOAT combines ingenuity, performance, and efficiency for a quality fastener that can improve the assembly and performance of any application. For more information, visit RIV-FLOAT’s product page, or contact us!
Recently, a customer of ours needed a special part in a hurry – and for good reason.
This closed end rivet nut was going to be used in a blood transfusion centrifuge that is used in the production of the COVID-19 vaccination efforts. If that wasn’t enough to expedite this order, the team in need of this part had a production line down.
Time and efficiency were critical.
The first email was received at Sherex Akron on a Monday at 12:03 p.m. explaining the dire situation. The small batch of products was made and shipped at 3:10 p.m. on Tuesday, ready to be used on the production line for Wednesday, with plenty of more on the way in the coming days and weeks to keep production running smoothly.
This was a fast, day and a half turnaround by the Sherex Akron team knowing how important this part is to hundreds of thousands of people who are suffering from this terrible pandemic.
“Thank you for making this an important situation within your company,” the customer said in an email. “Please extend my thanks to all the people involved with getting some parts ready to ship today.”
When Sherex said back in June that we were prioritizing projects directly impacting the mitigation and vaccination efforts of COVID-19 we weren’t kidding. This is just another example of the speed, competency and care, along with quality parts, the Sherex team delivered for our customer that we know will make a giant impact.
By Frank Genovese, Applications Engineer
There are dozens of different body styles of rivet nuts on the market today, including-body, half-hex, and full-hex in shape with further variations to explore from there. However, for as many different body styles, there are also a wide variety of rivet nut flange types as well.
Standard flange types are typically round, large, and vary in thickness depending on whether or not the part is considered “heavy duty” or not. However, in applications calling for more flush installations to the installation pane, smaller (and thinner) flanges are offered as an alternative. For half-hex and full-hex parts, these flanges often take a hexagonal shape.
This heavy duty round rivet nut has a thick flange to prevent pull out
For increased spin-out resistance, hexagonal body styles are generally the optimal solution. This requires the ability to create hexagonal holes in your material to ensure a proper installation. If this choice is not available to you, there are flange features that assist as well. Many standard parts are also offered with wedges under the flange, which bite into the material.
This FHK hex-style rivet nut has a very small flange, but offers superior protection from spin-out
For harder materials that may prove more difficult to bite into, select series of rivet nuts come with a keyway under the flange, which provide another method to further lock the rivet nut into the material after it has been installed. However, the latter method does require the ability to create a corresponding allowance for said keyway in your installation pane.
a keyway under the flange helps the grip in this military grade rivet nut
So what’s your choice?
While many flange styles are designed for particular intent, they also contain their drawbacks, so be sure to consider trade-offs when determining your specific needs.
Standard large flanges offer suitable strength, but do not offer flush installation without any further processing. Small flanges provide more flush installation, but decrease parts’ resistance to push-out failure conditions – for an improved flush installation without this issue, countersunk-head rivet nuts are a choice, but also require the ability to process countersunk heads in your material. Wedged heads are ineffective in harder materials, while keyways require further precise processing of your material to fit the part.
While the number of choices may be staggering at times, it all comes down to the critical needs of your overall design. And, of course, for larger solutions, custom designs that deviate away from standard options to fit your exact geometric or performance needs are often viable. This may include modifications to the wideness or the thickness of the flange, or the addition of features like wedges or keyways.
If you’re ever unsure as to what style of flange is best for your specific needs, our engineers are always happy to answer your questions on design or test solutions to find the optimal fit.
Did you know Sherex Fastening Solutions is a Made in America Fastener Company?
Our manufacturing plant in Akron, Ohio makes millions of American made rivet nuts, compression limiters, and inserts for composites every year. Our parts out of Sherex Akron belong in some of the hottest vehicles on the road today, dozens of commercial and military aircraft, general industrial applications, and department of defense products. In fact, our Made in the USA rivet nuts were relied upon when companies pivoted to make products that helped mitigate the spread of the coronavirus, like hand sanitizer and ventilator stands, along with other critical applications for hospitals.
Some of our most popular rivet nut lines are produced out of Sherex Akron, including our CAT and CFT Series, NAS Series, and custom rivet nuts and fasteners.
The CAT style rivet nuts has a low profile flange and can fit into a variety of different material thickness and material. This rivet nut could be a one fit solution if the material you’re looking to fasten has different thickness.
CAT Series Rivet Nuts
All NAS style rivet nuts are also made from our Sherex Akron location. The United States Department of Defense relies on Sherex NAS/MS rivet nuts for a variety of applications.
Our inserts for composite product line is used for structural attachments in plastic applications and are used extensively in the automotive and heavy truck industries as customer drive light weighting initiatives by switching to composite material for their components. In addition, Sherex adds compression limiters to these applications to ensure the mating component is not damaged due to the compressive force of the fastened joint.
NAS Style Rivet Nuts
Also, most custom rivet nuts are made out of Sherex Akron. With our staff of engineers and manufacturing facility, we’re able to see custom, American made rivet nuts from the design and manufacturing process all the way through quality control.
More upgrades are being made to the facility planned in 2020 to help increase capacity as demand as our Made in America rivet nut products continues to grow. More to come from Sherex Akron!