Fastener Technology

Tolerance & Fits (Part 1)

ISO Tolerance

A Vital Part of the Metric System

In a previous blog post, we wrote at length about the benefits of metric fasteners – and the use of the metric system, in general. The importance of tolerance systems was mentioned, but not expanded upon. The ISO tolerance system is, in essence, the key to global interchangeability.

The key to understanding the metric system as it relates to fasteners is the understanding of its tolerance system. The inch/pound system tolerance is done by minimums and maximums that are determined by design.

The ISO fits and tolerance system is based on a number/letter system that relates to the ISO tolerance chart. This chart is applied globally and allows the designed parts to be interchangeable.

The letters indicate the location of the tolerance and the numbers indicate the tolerance range. The bigger the number, the bigger the spread between the maximum and minimum tolerance. Capital letters show internal dimensions (holes, sockets key, etc.) while lower case letters refer to external dimensions (shaft diameters, pin diameters, width across the flats, etc.)

Each letter has its exact location related to a so-called zero line. The zero line refers to the nominal dimensions such as nominal diameter and nominal length.

In our next blog post, we’ll cover fits as it relates to tolerances, so be sure to check back next week! Until then, if you’re interested in engaging further about tolerance systems, please do not hesitate to reach out! Contact us at ProvenProductivity@bossard.com to get the conversation started.


November 20, 2015
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All About Washers

washers

The use of incorrect washers happens more than you might think – and it occurs all across the globe. What are the consequences of using the wrong washer? The strength of the join is reduced and the risk of loosening in a dynamic joint is increased.

So how do you know which washer to use?

Comparing and contrasting lock washers, split lock washers and ribbed lock washers can help create a better understanding of the advantages and disadvantages of both types.

Flat washers are up first. When used correctly, flat washers can help reduce surface pressure on softer materials, minimizing the loss of clamp load due to embedment. You’ll notice that the bearing area is often larger than a screw or a nut. In addition to producing more frictional resistance, flat washers also protect softer materials and reduce the risk of loosening due to embedment.

You’ll need to reference the fastener property class to determine the proper washer hardness. Choosing the wrong washer hardness can increase the risk of embedment.

Split lock washers are up next. There is a misconception that these are added to reduce the risk of rotational loosening, but the true objective with split lock washers is to reduce the loss of clamp load due to embedment. Correct use will reduce the risk of loosening due to dynamic forces.

But the strength of this type of washer is often overrated, leading to a much higher risk of loosening due to embedment. Split lock washers are only able to withstand clamp forces introduced by fasteners up to property class 5.8. It is also important to mention that their effectiveness is very low or even non-existent when used with heat treated fasteners of 8.8 (grade 5) and higher.

Ribbed lock washers stand apart. These washers feature ridges on at least one side designed to anchor themselves into the clamped parts, as well as into the bolt or nut’s bearing area. The friction in the bearing area prevents spontaneous rotational loosening of the screw or nut by increasing friction between bearing areas. This washer is also intended to reduce the risk of embedment.

For the reasons stated in the paragraph above, ribbed lock washers represent a viable and effective alternative to flat and split lock washers.

Not sold on the idea of ribbed lock washers for your application? We’re here to help! Contact us at ProvenProductivity@bossard.com to start the conversation.


November 06, 2015
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The Importance of Perfect Preload

Die Bedeutung der perfekten Vorspannung

Never underestimate the importance of preload. Failing to achieve the correct amount can have devastating and far-reaching consequences. Here, we’ll address two of the most common failures that can occur in the event of insufficient preload.

Mechanical overload failure – including embedment, crushing, yielding and fracturing – is nothing you ever want to deal with. But excessive preload can result in exactly that. Too much applied torque will lead to failure at assembly, and the consequences of that can have a domino effect. This will add to subsequent service loads and exceed the strength of the fastener/joint material.

Specific problem areas related to mechanical overload failure include differing thermal expansion rates, material, and creep especially when the joints contain plastic or gaskets.

Insufficient preload can lead to transverse slip of joint members, which in turn can cause loosening. Self-loosening, leaks, slippage, squeaks and rattles are all things you don’t want. Ensuring that the preload is sufficient will help avoid a lack of clamp force and the ensuing effects.

Obviously, the importance of preload cannot be ignored. Failing to implement the correct amount will certainly lead to issues and complications you’d rather not have to deal with.

Interested in learning more about the importance of preload and the potential consequences of failing to use a sufficient preload? Contact us at ProvenProductivity@bossard.com!


October 30, 2015
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Metric vs Fractional Fasteners

metric fasteners

Metric vs Fractional Fasteners

Can’t decide between metric fasteners and fractional fasteners? Allow us to settle the debate.

There are several benefits to using metric fasteners, chief among them being that metric dimensions are globally interchangeable, enabling you to procure parts from anywhere in the world.

For this reason, metric fasteners help facilitate international communication and trade, in addition to lowering in place costs. Products made in the United States are easier to service and maintain and also become an easier sell overseas, due in large part to the interchangeability of products.

The metric system is also simple and logical. The advantages are myriad. In addition to the aforementioned interchangeability, the metric system also benefits from increased accuracy, and has been applied by almost all nations across the globe.

Metric fasteners are subject to the ISO tolerance system. This system system is the key to achieving lower cost and interchangeability globally.

For more information about the benefits of metric fasteners, click here.

The Bossard website also features a tool for converting between metric and inch fasteners. This converter – which can be found here – offers best proposals as you work toward a compromise.

Not sold on metric fasteners over fractional fasteners? The conversation doesn’t have to end here. Contact us at ProvenProductivity@bossard.com! We’re happy to continue this discussion with you.


October 26, 2015
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Fasteners for High Temperatures

Fasteners for High Temperatures

Temperature is an important factor to consider when determining which fastener is best suited for your application. Failing to take temperature into account can have severe consequences for your application. Here, we’ll cover various temperature ranges and the ideal fasteners for each one, with a specific focus on higher temperatures.

Temperature Range from -50 Degrees Celsius to 300 Degrees C
According to the ISO standard, standard property classes can be used for this particular temperature range. Your standard off-the-shelf 12.9 can be used, but it is important to remember that the 12.9 is limited to a specific range between -10 Degrees C and 250 Degrees C.

Above 300 Degrees C (570 Degrees Fahrenheit)
Low carbon steel or low ally steel can be used up to a ceiling of about 350 Degrees C (660 Degrees F). For this temperature range, the carbon content should be less than 0.4 percent.

Above 350 Degrees C (660 Degrees F) to 600 Degrees C (1,112 Degrees F)
Low alloy steels with an alloy element such as chromium, molybdenum, and vanadium are best suited for this temperature range. In addition to offering greater resistance to relaxation, these materials also possess tensile and yield strength that typically do not exceed that of property class 8.8.

Towards the higher end of this temperature range, best practices suggest the use of steels with higher content levels of chromium, molybdenum and vanadium.

Similar to the previous temperature range, the carbon content should be less than 0.4 percent.

Above 540 Degrees C (1,000 Degrees F)
Austenic steels, which are not heat treated, are best suited for this application. Their strength is achieved through work hardening. But depending on the environment, austenic steels or super alloys may have to be used for this temperature range.

Figuring out what best works with each temperature can be tricky. But we’re here to help! Contact us at ProvenProductivity@bossard.com if you have any questions about finding fasteners for high temperatures. The answers to your questions await!


October 16, 2015
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Bossard Speed Rivets

Speed Rivets

Bossard Speed Rivets

What you need: An effective and efficient rivet engineered for the purpose of rapid and blind-sided installation, ideal for use with different materials and thicknesses.

What we have to offer: Bossard Speed Rivets.

You have a need – and we have the product to fulfill it.

The Bossard Speed Rivet is everything you’d want it to be. Pre-loaded on a one-way mandrel, this particular rivet can then be introduced right into the nose of the riveting machine. This allows you to fasten up to a continuous rate of 70 rivets per minute.

As far as materials go, the Bossard Speed Rivet can be used to fasten metals, plastics, composites, fiberglass and electronic components. The sheer of variety of different materials this rivet can be used with is evidence of how useful this particular product can be.

Electronic applications, sheet metal applications, vehicle construction, electric components, household appliances and metal cabinets are among the applications ideal for use with the Bossard Speed Rivet. Few similar products can compete with that kind of versatility, at least in terms of applications.

If quality and security are a concern, you can rest easy. The Bossard Speed Rivet, as is standard procedure with our products, is built to stand up to even the most painstaking scrutiny. There is no risk of losing the residual mandrel due to vibrations.

Bossard Speed Rivets are also held in place in the riveting tool to avoid a setback from being dropped onto the floor or into the application. Like we said before, we’ve covered out bases.

Interested in learning more about the Bossard Speed Rivet? Contact us at ProvenProductivity@bossard.com. Remember, this blog post is the tip of the iceberg when it comes to our products. All it takes is one e-mail to see the rest of what we have to offer!

For more shopping options click here.


September 25, 2015
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Benefits of Fastening with Magnesium

Fastening with Magnesium

Benefits of Fastening with Magnesium

I understand you’ve settled on using aluminum with your fastening application. But all I have is one question before you move forward: Have you considered magnesium as an alternative?

If you haven’t, you might not be aware of the benefits you’re missing out on.

One of the biggest advantages of fastening with magnesium is the reduced weight, as magnesium is approximately 30 to 35 percent lighter than aluminum.

Magnesium also boasts the highest strength-to-weight ratio of all common structural metals. For example, consider the wall thickness of 1.5mm magnesium versus 3mm aluminum.

Closer tolerances are also possible with the use of magnesium. Thixomolding, the process of heating magnesium into the barrel of a press, comes to mind as one of the chief possibilities.

In terms of production die life, magnesium also lasts longer than aluminum. There are numerous performance benefits from using magnesium, including better rigidity.

There are a number of items in which fastening with magnesium can be used. All you have to do is look around the house, in some cases. Electronics, powers tools (drills, saws, nailers, etc.), lawn and garden equipment, sports and leisure equipment and automotive parts are among the list of items.

Bolts and nuts, machine screws and thread-cutting screws are just a few options at your disposal in terms of fastening with magnesium, so your choices will not be limited.

Not quite sold on the idea of fastening with magnesium? Not a problem. Contact Bossard at ProvenProductivity@bossard.com and we will put you in contact with someone who can answer all questions you might have. Once you’ve started using magnesium with your fastening applications, aluminum will feel like a distant memory.


September 18, 2015
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The Hidden Potentials of Fastening

Das verborgene Potenzial der Verbindungstechnik

The Hidden Potentials of Fastening

Bossard is dedicated to helping our customers streamline their processes and become more efficient. Sourcing, design, engineering, logistics, handling, ordering, quality, stocking and assembling are all important elements to analyze in the interest of boosting your productivity. Want to reduce your production time and go lean? Watch the video below to find out how.

The first step down the path toward Proven Productivity was watching that video. The next step? Contacting Bossard at ProvenProductivity@bossard.com. You won’t know your full potential until you’ve met with our experts. We’ve been engineering success since 1831 — let’s get started on yours in 2015.


September 04, 2015
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The Challenge of Self-Loosening

Self-Loosening challenges

The Challenge of Self-Loosening

Bossard has built its reputation on having mastered the science of fastening, and that includes developing innovative solutions for some of the most common challenges in the industry.

Self-loosening is chief among the challenges that the fastening industry has had to deal with. The mere mention of self-loosening is enough to draw the attention of product designers, production specialists, industrial engineers and maintenance and safety officers. The reason? It comes down to safety, and everyone is eager to listen where there are new solutions being presented.

Threaded fasteners can be found in transportation systems, recreational and sports equipment, testing and measuring equipment, digital gadgets and even children’s toys. The popularity of threaded fasteners is based largely on their numerous benefits, but we can’t forget about their weaknesses either.

And self-loosening is one of the most glaring risks with threaded fasteners.

Why do threaded fasteners self-loosen? In the simplest of terms, vibrations are what cause fasteners to loosen, in most cases. Vibrations lead to fatigue failure, as the clamp force on the joint is reduced and the fastener is then subjected to bending loads.

At the moment, there is no universal solution for countering the loosening of fasteners. But designers and engineers have emphasized the need to ensure there is sufficient clamp force on the joint interface, in addition to also producing a design that can withstand the effects of embedding and stress relaxation.

For a more in-depth discussion regarding self-loosening and other challenges associated with fastening, do not hesitate to contact Bossard at ProvenProductivity@bossard.com. You can also register with our company website to download a whitepaper with more information about self-loosening joints.


August 28, 2015
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bigHead® with Lightweight Applications

bighead with lightweight applications

Secure, simple and versatile – bigHead® fasteners are everything you could want in a fastener. For lightweight applications, accept no substitute for what bigHead® has to offer.

In addition to being discrete and secure, bigHead® fasteners are an efficient option for your lightweight application. The list of possible applications includes cabin panels, interior trim, external cladding, bumpers, bump stops, front end modules, molded panels, light clusters and more.

bigHead® fasteners can be embedded or even surfaced mounted with a structural adhesive, allowing them to be more versatile. These fasteners, when used in lightweight applications, are dependable and also allow you to make more efficient use of your time.

Aston Martin, Bentley, McLaren, Ford and Fiat are among the automotive companies that utilize bigHead® fasteners in their vehicles. On top of that, this particular brand of fasteners is also popular with several kit car manufacturers and enthusiasts.

bigHead® is also a BMW approved supplier for Rolls Royce Motors.

Just based on what we’ve shared with you, it is clear that the possibilities are almost limitless when it comes to bigHead® fasteners and lightweight applications, particularly in the automotive industry.

As mentioned in a previous blog post, Bossard will be attending the 2015 Detroit Global Automotive Lightweight Materials (GALM) Show from August 18-20, so that will present an opportunity to both share and grow our knowledge of how bigHead® fits with lightweight automotive applications.

For a more in-depth discussion on how bigHead® fasteners can be used with lightweight applications, contact Bossard at ProvenProductivity@bossard.com.


August 21, 2015
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