Compression limiters are typically cylindrical components made of steel, stainless steel, brass, or aluminum that prevent overstressing of usually plastic or composite material and fastener clamp load loss during fastener installation. They can be used integrated with a fastener, such as a rivet nut, to provide metal to metal transfer of forces during the joint assembly.
This helps to prevent the surrounding material from being deformed or damaged.
Essentially, the compression limiter can fill a gap for a metal on metal load transfer as to not deform the material. So when the fastener, such as a screw or bolt, is tightened, the compression limiter is compressed between the fastener head and the metal parts being joined for a compact assembly.
The designs of a compression limiters are limitless. They can very large or very small, have knurls or wedges, or just be a smooth body cylinder like a spacer. What all compression limiters have in common, though, is that they are UNTHREADED. In some scenarios a bolt may pass through the compression limiter, it doesn’t have threads to keep the bolt in place.
What applications are compression limiters used in?
Metal compression limiters are commonly used in industries such as automotive, aerospace, construction and agricultural equipment, and in general construction where high strength and reliability are crucial. They are often used in applications where the joint must withstand significant loads or stresses, such as in structural connections or engine components. They are oftentimes used to not distress the base material.
How they are made?
Compression limiters are either cold-formed or machined. Sherex engineers design compression limiters for specific applications, so many of these parts are unique to the project they were designed for.
With high volume installations of rivet nuts, automation is a best practice method. It’s faster than human installation, installations are perfect (and if they’re not the system will let you know), and it doesn’t need a human to install the rivet nuts. But when using a hexagonal hole to install hex body rivet nuts using automation, this is where things get tricky.
Optisert vs. Hex Body Rivet Nut
The automation feeder needs to be able to line up the points of the hex body rivet nut with the points of the hex body hole, perfectly. It’s not ideal, but possible through more expensive automation equipment. With a round body rivet nut into a round hole, there’s no need to worry about the points lining up… because, well, there’s no points on a round body rivet nut or a round hole!
Oh yeah, but what about performance?
So yes, hex body rivet nuts are recommended. It’s the best rivet nut at resisting spin-out. BUT, Optisert can hold its own. Its performance metrics are greater than a half hex body style rivet nut, and more similar to a full hex body style rivet nut in some base materials (softer materials like plastic, composite, aluminum). Plus, Optiserts are less expensive than full hex body style rivet nuts.
So when deciding between full hex rivet nuts and round body rivet nuts for automation, rivet nut performance might not be the first criteria. Ease of installation for the automation system to run efficiently will be a high priority. With Optisert’s performance similar to a hex body rivet nut, and it being a round body, Optisert might very well be the best rivet nut option for automation on the market today.
Sherex has been working for over five years on a round body rivet nut that can perform comparably vs. a half hex body rivet nut. This rivet nut can do that.
We are still going to recommend a full hex body rivet nut if you can make a hex hole – especially in harder material like steel and stainless steel. But if a round hole is the only hole that can be produced, especially in softer materials like plastic, fiberglass and aluminum, Optisert’s performance is impressive.
“We’ve had over five years of product development to get the performance where we want it,” said Sherex Engineering Manager John Knechtges. “We’ve done similar wedgehead, knurled rivet nuts as specials for projects, but this standard part has unmatched performance. We’re really proud.”
Let’s look at the numbers:
Optisert vs. CAL Series and CAL Wedge round body:
Optisert vs. Half Hex:
The numbers speak for themselves. Optisert spin-out performance is closer to the performance of a full hex rivet nut than a normal, round body CAL rivet nut, and GREATER than a half hex rivet nut.
With knurls underneath the flange that bite into the material, resistance to spin out is very extraordinary. Spin-out occurs when the rivet nut spins into the hole it’s installed into. Spin-out would potentially occur in applications that experience heavy vibration, or in applications that experience a lot of strain and force.
For industries that are continuously looking for lightweighting options, like automotive and heavy truck, Optisert is an ideal option for a threaded insert fastener. Optisert also comes in a closed end option with a seal that comes standard. The seal does not compromise grip, and helps keep dust and water out of the base material.
It was great getting back to some normalcy. But with getting back to normal and ramping up came with challenges many manufacturers ran into this year: SUPPLY CHAIN. With that said, we feel we navigated supply chain issues better than our competitors and we even made moves that will hopefully mitigate those risks in the future.
Let’s take a look at some of the highlights from Sherex this year!
Operators LOVE our Calibration Unit and our Process Monitoring Units
Sherex’s Hand Tool Calibration Unit
When we released our Hand Tool Calibration Unit in 2020, we knew this would be a great tool for any installer. And after two years, we keep getting glowing praise. We hate to toot our own horn, but the tool is awesome. There are so many features the tool can provide, like exporting historical data, showing the recommended installation force on Sherex rivet nuts, and even graphing those recommended forces on to calibration unit to make sure the tool is inside of those parameters. By periodically checking the force of any spin-spin or spin-pull tool, you’ll feel confident the tool is operating how you want it, decreasing the guessing game on the pulling force, waste, and rework.
Some of our automotive tiers have had dozens of our FLEX-5 Process Monitoring Tools installed this year. Sherex Process Monitoring Tools let operators know if the rivet nut installation was perfect, instantly. Sherex sets the tool up to determine if the install was correct based on a variety of parameters: hole size, material, material thickness, rivet nut, rivet nut size, pulling force of the tool, etc. When all those parameters qualify, the system reads it as a good installation. This kind of tool combines quality and efficiency, and lets OEMs know, with data, that installations were perfect or not OK. These tools are perfect for high volume installations like on an assembly line and meets the process monitoring requirement many auto manufacturers require.
Our customers have nothing but great things to say on both these quality tools – you must try them if you haven’t already!
Sherex Poland and Sherex UK locations are off and running
We opened Sherex Poland last year and Sherex UK in 2019 and both locations have been building trust and supplying millions of our quality rivet nuts, threaded inserts, clinch nuts, wedge locking products and tools throughout Europe.
These locations serve as engineering, sales, customer support and warehousing for Europe, bringing us closer to our European customers and therefore, decreasing the total length of our supply chain. This year, new customers were pleasantly surprised we had stock AND could ship quickly! Great year by both Sherex Poland and Sherex UK.
Sherex Akron gets big upgrades, improving supply chain
New Part Former Machine at Sherex Akron
Sherex Akron, located in Akron, Ohio, makes all of our aerospace and Department of Defense parts, along with millions of other parts for a variety of other industries, put online two new part formers that as part of Sherex’s global capacity plan. These cold formers have allowed us to diversify the products we make in Akron while decreasing lead times. Akron still is capable of doing many short run jobs, but these part formers will really help with some of the major projects we’ve won throughout the year. Look for lot more product coming out of Akron in the future!
Have a Made in America requirement? Keep Sherex Akron in mind!
Optisert® is coming…
Sherex’s Optisert Rivet Nut
We’ve been talking about it for quite some time, but now it’s ready to be released. Sherex’s new round body rivet nut, Optisert, is set to be released in early 2023. Once released, Optisert will be the best performing round body rivet nut on the market. The combination of knurled body and underhead wedges give it superior strength when installed in softer material — its performance matches and in some cases is greater than a hex body rivet nuts!
This will be the “New Standard” when it comes to round body rivet nut and performance. Stay tuned!!
Look for more industry specific content in the future
Keep a look out for some of that industry specific content to show how Sherex can help make applications in all industries get assembled easier and perform better.
These are some of highlights this year and our strategy going into 2023 and beyond.
Overall, Sherex had a strong year and we’re proud of our team to make that happen. One thing that will never change is our desire to find a solutions to your fastening problem. Customer service is key to our success, and we promise to provide the engineering and customer support you need from design, to manufacture, to assembly!
We wish everyone a happy holiday and best wishes in 2023.
What do you need to be successful at installing rivet nuts? Depends who you ask.
For some, it’s just parts and a rivet nut tool. But it really should be more than that.
Let’s take a look at what every rivet nut installer should have at his or her rivet nut workstation:
Hand Tool Calibration Unit Unless you’re installing parts with a process monitoring tool, you need a Hand Tool Calibration Unit. The Hand Tool Calibration Unit shows the pulling force of the rivet nut installation tool, so users know the exact installation force being used to install the part. A dip in pulling force may set the part improperly, leading to rework and time spent fixing parts the user already installed.
Calipers Every fastener installer needs calipers at their workstation. Calipers are used to measure the dimension and length of an object. This could be the measurement of the hole, or the installed length of the rivet nut. They help ensure the part was installed correctly too.
Rivet Nut Catalog The rivet nut catalog has loads of information the user may need during their installations. Everything from grip range, installation length, hole size, part number nomenclature and more. It’s a valuable reference to make sure you’re installing the correct part.
Hex Tool Hex tool is used to increase or decrease the pressure on your hydro-pneumatic rivet nut tool. By using the Hand Tool Calibration Unit to check the pressure, you’ll know whether to turn the pressure up or down on your rivet nut tool.
Vice Grips Vice Grips are used to install the headset on the Hand Tool Calibration Unit and change the headset on your tooling.
Rivet Nut Tooling It goes without saying, you need rivet nut tools to install rivet nuts. There are a variety of fastener installation systems you can use, but preferably it would be a hydro-pneumatic tool as it offers fast installation with the ability to spin the part onto the mandrel itself.
The last two items are pretty obvious, but the others are really necessary to ensure a perfect installations. The Cal Unit so you know the pulling force, the calipers to make sure measurements are to spec, Rivet Nut Catalog to see specs of the part you’re installing, hex tool to change the pressure of the tool, and vice grips to change the mandrel of the Cal Unit. Oh, and you know, rivet nuts and rivet nut tool.
All this will make for some successful installations!
As one could imagine, the Aerospace Industry is highly regulated and guided by a variety of certifications and standards that must be adhered to for performance and safety. Sherex Akron is an ISO 9001:2015, QSLM Class 3 and Class 2 certified through the Defense Logistics Agency, and AS9100 compliant. Sherex’s CAGE Code is 7EK30. What does this mean? Our facility and parts have been qualified and meet a certain criteria required by US aerospace manufactures and the DoD. Manufacturers can be sure the parts they receive live up to the high standards required by these associations.
Remember, these parts not only have to hold the plane together, they have to do so while under harsh conditions, like gravity, pressure, turbulence, and vibration. They must be have high tensile strength and have high corrosion resistance while typically being lightweight.
Sherex NAS 1329 and NAS 1330 parts are used in a variety of airplanes and helicopter applications.
Sherex SX aerospace rivet nuts are made of a variety of materials like steel, stainless steel or aluminum, and they are usually round body style with either a flat head (NAS 1329) or countersunk head (NAS 1330). Most of these parts, especially those made of aluminum, are cold formed, so heat is not needed to produce these pieces. Aluminum is not only lightweight, but is resistant to fatigue and features high tensile strength.
Sherex NAS 1329 and 1330 rivet nuts are supplied to a variety of aerospace and DoD manufacturers, including helicopter manufactures. Almost all of applications of Sherex NAS/MS style rivet nuts belong in the cabin and are not considered critical components (like holding the wings onto planes, or landing gear), but nonetheless play an extremely important role in the fuselage and cockpit. One specific application went in the floor of a military helicopter keeping armor together on the floor, and another NAS rivet nut went in the overhead compartment of one of the most popular commercial jet liners ever built.
Aluminum NAS1329 Style Rivet Nuts
Sherex has a number of ongoing projects with the DoD and other Aerospace manufactures and has lots of experience in this industry. To learn more about our Akron capabilities, see our DoD Statement of Capabilities and how we can provide extremely quality, and durable fasteners for any aerospace project.
On this clinch nut, there are displacement lobes that force the sheet metal to flow into the locking groove when pressed in. This allows sheet metal to remain flat with no indentation and providing the nut with high push out and torque values. The base material remains flush.
This style of clinch nut is designed for thicker sheet metal applications from 2mm to 10mm thick, and is compatible with Class 8, 9, & 10 hardware depending on application requirements.
Front and backside of installed ACN and ASN Clinch Nuts. Notice the flush installation on the front side.
This clinch nut has extensive knurls that push into the material. During installation, sheet metal is formed into an undercut section on the nut collar by the die button and the knurled ring. As a result, the nut has high push out and torque values, and space requirement is minimal due to the small outer diameter and flat installation surface.
The ASN clinch nut can be used in sheet metal applications from 1.5mm to 10mm thick, and is compatible with Class 8, 9, & 10 hardware depending on application requirements.
The ARN Series clinch nut is a unique style of clinch nut that has locking grooves to dig into the material when pressed in, while the neck part of the clinch nut is crimped over the base material using a special die, making the base material “almost flush.” Locking grooves are the clinch feature of the nut, providing high push out, pull through, and torque values, even in very thin sheet materials. The nut can be installed using several different installation methods depending on the sheet material thickness, hardness, and installation clearance.
Can be used in sheet metal from 0.4mm to 6mm thick, and is compatible with Class 8, 9, & 10 hardware depending on application requirements.
Custom Clinch Nuts
Some projects that require clinch nuts might need a higher tolerance grip range, or something that can bite into the material more, or a different coating. Sherex can design-in and manufacture special clinch nuts for your project. Be sure to look at our post Rivet Nuts vs Clinch Nuts to read the differences and similarities between the two fasteners!
If considering a clinch nut for your project and want to discuss what the best clinch nut for your project will be, contact us!
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.
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
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.
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.