Fastener Technology

How to Match Nuts, Bolts, AND Washers

When selecting fasteners that are to be assembled together, it is important to consider their strength compatibility. The nut should always be stronger than the bolt, so when using higher strength bolts, such as metric class 10.9, make sure to use the correct, corresponding nut. In this case, a class 10 nut would be correct. Stronger nuts may be used with lower strength bolts without any problems.

Strength of washers should also be considered, but are often overlooked. Using non-heat treated washers with heat treated hex head cap screws can cause joint settling as the relatively small bearing surface of the cap screw can embed itself into the soft washer over time, causing a loss of clamp load.

Standard metric flat washers have class designations that can be paired with heat treated bolts. Below is a compatibility chart that will help you make the right choice.

Check out the “Technical Resources” section at www.bossard.com for more information on selecting the proper fasteners, or reach out to us at ProvenProductivity@bossard.com with any questions.

 

Doug Jones
Applications Engineer
djones@bossard.com

 

November 03, 2017
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The Importance of Friction in Your Bolted Joint: Part 2

When doing research for your bolted joint it is important to understand the coefficient of friction of the finish of the fastener. There are many different options for coatings that will give you different ranges in values. Typically, those values are tested to a certain specification. Whether it’s an OEM specification, or per the ISO 16047 standard, each one can have minor differences (if you have questions on standards reach out to a Bossard engineer). So what do those values actually mean and how are they relevant to your joint?

Most of the testing that is done to validate the values of the coating is done on M10 surrogate bolts with a standard hex head cap screw. They are tested in lab conditions with either a plain finish washer or nut that is cleaned and degreased or with different variations done in a lab setting. The cause for concern is using those values in your joint. The values can change depending on your bearing surface and your mating threads (material, surface condition, lubrication, bearing surface area, etc.). As stated in previous Proven Productivity blog posts, it’s important to understand the relationship so you prevent costly errors down the road.

That is why we at Bossard always recommend doing bolted joint testing. We have the capability to perform joint testing so we can help you better understand the coefficient of friction and the torque tension relationship in your joints. We can perform testing onsite at your facility or you can visit one of our engineering design centers.

Contact us at ProvenProductivity@bossard.com for more information.

Jon Dabney
Application Engineer
Jdabney@bossard.com

October 13, 2017
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Why You Should Respect Your Fasteners

Take a minute to think of some of the most amazing mechanical marvels we have today: electric vehicles, exo-skeletons, cell phones, wind turbines, and many more. What do most of them have in common? They are all held together with some type of fasteners.

Now think about your product. What happens if the fasteners fail during use? At best, the customer is not happy and may look at other brands for their next purchase. At worst, damage to property or personal injury could result.

So, why are fasteners always the last thing we think about in our design? It’s true that assembly is the last step in the product design process, but fastener selection should be carefully considered in the early product design stages to ensure the best and safest product. Early fastener selection is also associated with time and cost savings making your process more lean and efficient.

Not sure what is the best choice? Have questions about what’s readily available or what’s new in fastener technology? Contact your fastening solutions provider to help you select the best hardware for your project. Don’t wait until two weeks before production starts!

Contact ProvenProductivity@bossard.com for information about the latest and greatest hardware innovations, and get help with your next project!

Doug Jones
Applications Engineer
djones@bossard.com

October 06, 2017
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Why Quality Fasteners are Worth It

You’ve spent months on your design doing careful analysis and selecting the right materials. You are finally getting close to production – but wait, you haven’t selected a fastener supplier yet. You need mostly standard fasteners, except for those few specialty print parts. It’s just fasteners; how hard can it be?

 

The next step is to turn over your fastener list to the buyer and have them find the cheapest hardware they can negotiate to save a few pennies on the product. After all, it doesn’t matter where they come from. All fasteners are the same, right?

This scenario may be a bit harsh, but is all too often true. If manufacturers are making standard fasteners, they should be using the same fastener standards. Unfortunately, some manufacturers take short cuts to keep costs down in this highly competitive market. Some low-cost providers may make perfectly good fasteners 90% of the time, but is 90% good enough for your design? Assembly issues, failures in the field, warranty claims costs, and poor customer satisfaction when a new widget breaks or doesn’t perform as advertised can be very expensive and time consuming.

 

My advice is this: know where your fasteners are coming from. Here are some questions you can ask yourself before selecting a supplier:

  • Does the manufacturer have good process controls?
  • Are they tracking reject rates both internally and externally?
  • Are they subcontracting fastener finishes or heat treatment?
  • Do the subcontractors have good process controls?

 

Contact us through ProvenProductivity@bossard.com and see what steps we take to ensure good quality fasteners.

 

Doug Jones
Applications Engineer
djones@bossard.com

 

September 22, 2017
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Length of Engaged Thread

Length of Engaged Thread

Length of engagement is important to understand. The required minimum length of engagement changes for different materials and hardness of said materials. This is something that needs to be determined during the design process.

When screws need to be fully loaded in tensile, it is important to note the strength of the material that the ‘nut’, or female threaded component, is made of. The minimum length of the engaged thread will depend on it. Ultimately, it is important to achieve the required minimum length to give the joint the durability it needs.

Below are some examples of recommended minimum lengths of engaged thread in internal threads based on the material of the nut component for heat-treated steel bolts. These have been determined from practical trials:

Recommended minimum lengths of engaged thread in internal threads.

Make sure the toolbox of information needed to determine the proper length of engagement is readily available. Reach out to us at ProvenProductivity@bossard.com if there is any questions regarding this!

June 02, 2017
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Fatigue Resistance in Fasteners

Fatigue Resistance in Fasteners

Simply put, you want your fasteners to hold up under many situations including conditions of changing load. However, some fasteners cannot hold up to the challenge. One of the most common forms of fastener failure is fatigue. That is why fatigue resistance and strength is something to look for in your fasteners.

A fastener can experience fatigue for a variety of reasons including assembly parameters, fastener material, geometry, and stress on the fastener. Fatigue often occurs in the first load-bearing part of the thread, and it can be detrimental to your project. This means your design must allow for screws to increase its fatigue strength. However, the fatigue strength of fine threads decreases with increased rigidity and fineness of thread, so there are some things to keep in mind with fatigue strength in your fasteners.

There are ways to increase the fatigue strength of your screws. These would include measures that reduce the effective peak stresses or prevent combined loading.

Check out some options for increasing your fatigue strength:

  • Use longer screws rather than shorter screws
  • Use screws with waisted shanks
  • Use pins or fitted shoulder screws to absorb lateral forces
  • Adequate and controlled pre-stressing of the screws

Reach out to us at ProvenProductivity@bossard.com to learn more about fatigue resistance and to find the fastener with the perfect fatigue strength for you.

May 26, 2017
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bigHead® for Wind Turbines

bigHead® for Wind Turbines

Solving your fastening problems is what bigHead does. Whether it is a difficult project or an extreme environment, we can come up with fastening solutions tailored to your needs. That is what bigHead did for offshore wind turbine maintenance hatches.

Siemens nacelle suppliers approached bigHead with a fastening problem. They recently came up with a composite hatch to replace a steel panel for covering a maintenance hatch. The only problem with the composite hatch was fastening it with traditional bolt fixings. This was a challenge because two people were required to perform the operation—one inside and one outside the nacelle. That made the operation not only less safe, but more challenging and time consuming to perform.

However, bigHead and Siemens came up with a solution through prototyping and extreme testing to make sure the fastening solution could hold up under the harsh conditions that the offshore wind turbines endured.

The solution for these offshore wind turbines was surface bonding the 316 marine grade stainless steel bigHead to the outer skin of the nacelle and passing the threaded stud section through its composite structure. This means the panel can easily be secured or removed by one person from the interior of the structure. The bigHead’s large perforated head allows a generous flow of adhesive to firmly secure it in position and its outer surface includes an over-moulded insulation layer that safeguards the nacelle against lightning strikes.

bigHead and Siemens worked together to create the perfect fastening solution for a tough problem. bigHead has been manufacturing its distinctive and leading brand of discrete bonding fasteners for over 50 years and has extensive experience across a wide range of industries where formed and molded composite products require discrete and completely secure fixing. Applications range from carbon fiber panel fixing in specialist and luxury car production to building and construction, railway carriage construction, marine and boat building, and more.

Do you have a tough problem that needs a fastening solution? Reach out to us at ProvenProductivity@bossard.com and we can find your perfect solution or even develop one for you.

May 19, 2017
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Fastening Solutions for the Rail Industry: bigHead® and FRP materials

Fastening Solutions for the Rail Industry bigHead® and FRP materials

Improving efficiency and reducing costs are two focuses of any industry or any business and mass transit is certainly not an exception. The rail industry is always looking at embracing new materials and new production techniques to improve their processes. bigHead® is a fastening solution that will help do just that.

FRP Materials and the Rail Industry

One of these new materials that has become popular recently in the rail industry is the use of fiber-reinforced polymer composite (FRP) materials. The FRP materials help to create lightweight but high-strength structures, and they are also good for design flexibility.

bigHead® Fastening Solutions

However, to use these materials successfully, you need a fastener that is safe, secure and discrete. This is where bigHead® comes in. Fastening solutions from bigHead® offer you advantages over many other fasteners. Check out the reasons to look into bigHead® below:

  1. bigHead® fits your project perfectly – You can receive a wide range of standard or customized product solutions, which means bigHead® will be a perfect fit.
  2. bigHead® can save you time – With bigHead® you can fasten without drilling, which offers you many advantages. You will save time by not drilling, and you will also preserve your materials and keep them strong because you don’t have to create holes in your materials. You can use bigHeads to complete and assemble pods into the vehicle structure. Also, bigHeads can be used on the inside of your pods and structures to fix internal panels, flooring, signage and even trim into place.
  3. bigHead® can reduce your assembly costs – When you use bigHead® fasteners, they can be embedded in composite materials during the lay-up process or they can be surface bonded with adhesive. This means you don’t need a secondary assembly process which can reduce your manufacturing costs.

Every company and industry is looking for innovative ways to make their products and services more successful. At Bossard, with our bigHead® fastening solutions, we are providing the solutions to make your products more successful. You can save time and money with bigHead®, and you can rest assured that these solutions work.

If you have any questions, contact us at ProvenProductivity@bossard.com.


April 28, 2017
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5 Benefits of Metric Dimensioning Fasteners

Metric Fasteners

When looking at fasteners, you have to decide whether you want imperial fasteners or metric fasteners. When designing new products metric dimensioning should be considered as a low cost solution to fastener assembling.

Metric fasteners most often win out over imperial fasteners and here’s why:

  1. It is a simple form of measurement with a base of whole numbers. This can help reduce the number of fasteners in a bill of materials.
  2. They are interchangeable in a global market. Parts can be assembled globally because of the availability of tools. Replacement fasteners can be purchased from local sources. Interchangeability was the key reason the automotive industry has moved to the metric form of fasteners.
  3. The metric system is the most precise form of measurement. It has been adopted by the medical industry as well as the aerospace and electronics industries.
  4. Metric thread falls between an inch course and fine thread. This allows the designer to take advantage of both thread types. It’s a better choice for vibration resistance as well as providing a larger stress area in the cross section of the screw. A commercial finish can be applied without gaging issues.
  5. Standard metric fasteners are manufactured in accordance to the ISO 4759 standard. This is a global base hole system that uses a letters and numbers system to determine a standard plus/minus tolerance for threaded fasteners.

These benefits will aid long term cost savings in design, manufacturing, and assembly, as well as product longevity in the market. If you are interested in other ways of making your business more productive, check out our product solutions and our Smart Factory Logistics.

As always, if you have any questions or concerns, let us know how we can help you by contacting us at ProvenProductivity@bossard.com.


April 21, 2017
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Fasteners for Composite Materials

composites

Composite materials have become more popular to use in various projects because of their versatility. Composites are often lighter and stronger than traditional materials, so they are a go-to for projects. However, it can be a little more tricky to find fastening solutions for composite materials. Fasteners such as bigHead® and ecosyn®-BCT were created for more complex materials and situations like working with composite materials. Learn what bigHead® and ecosyn®-BCT can do for you.

bigHead®

These fasteners are made so any attachment points such as pins, nails, nuts, threads, hooks, etc. are attached to the head or base plate via a weld point. This construction allows bigHeads to be integrated into your project “invisibly.” It also means these fasteners don’t require holes in your composite materials, so your material can stay strong. These fasteners can either be embedded into the composites or surface-bonded to the composites so you don’t compromise the composite material itself.

ecosyn®-BCT

ecosyn®-BCT rivet nuts have cross holes on the shank to determine where the rivet nut will collapse to allow it to be installed in non-conventional blind applications. ecosyn®-BCT rivet nuts give you a resilient connection because it applies minimal stress around the base material so there is no damage to your materials.

Both bigHead® and ecosyn®-BCT work hard on your tough projects. These fasteners were designed to help out on those projects that are hard to handle. Using these fasteners with composite materials will help you to have a strong, stable and resilient product.

To find out more about fasteners for composite materials, or to find out which fastener is perfect for your project, contact us at ProvenProductivity@bossard.com.


April 14, 2017
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