Wire thread inserts from Challenge Europe

Specialist threaded fasteners often need help in forming the best attachment to soft core materials such as aluminium or magnesium alloys. Challenge Europe are pleased to announce their stock, advice and production service operation for a comprehensive range of wire thread inserts, available in both tanged and tangless variants, or screw thread inserts which provide high performance internal threads in castings where light weight of the complete assembly is a major issue.

These inserts provide significantly improved performance over the substrate, enabling bolt tension to be maintained under severe conditions of vibration, thermal stress and corrosive action.

Challenge Europe wire thread inserts represent an extensively proven well accepted technology and are exceptionally effective in aerospace, auto industry, electronics, medical and related industries.

Use of wire thread inserts enables manufacturer assemblers to access the best performance characteristics of a multi-material approach where combinations of metallurgy are required. Standard material is chrome nickel austenitic stainless steel which is compatible with most substrates and is both hard-wearing and corrosion-resistant.

A wide range of other materials and surface finishes are available to ensure optimum performance in a variety of thread forms and identification colours. Contact us to specify your needs.

Challenge Europe address the dangers of "Internet specification" of threaded fasteners

With all the benefits of the internet it has become apparent that there are dangers – who of us has not come across the life-critical disease “we have self-diagnosed” online, or the false news/conspiracy theory which can reinforce our worst fears?

At a professional industrial level, Challenge Europe often find design engineers overlook the sophistication of threaded fasteners and fall into the trap of “internet specification” or “specification by CAD system”. A practice which seems to derive from pressure of time coupled with the perception that fasteners are low-end product and that sourcing can be done over the internet, relying on urgent sample supply in case of doubt.

An experienced fastener supplier can provide a wider knowledge at the level of advice in new product development, re-engineering and in problem-solving where difficulties arise. It is increasingly difficult to find this level of expertise outside of specialists such as Challenge Europe.

Challenge Europe address the problems of over specification in threaded fasteners

Ultimately, one can never know completely how a fastener will function in-situ until you try it which is why accelerated aging trials and extended excess load tests are frequently performed to ascertain a realistic safety margin. Guidelines from hard-won experience can normally be accessed, but sometimes an unusual situation needs to be evaluated or perhaps a replacement of the exact same type is simply not available and a suitable replacement is required. It is easy and tempting to over-specify, but Challenge Europe can help.

Fasteners can almost be regarded as active components, given the changing loads and environments they are often called upon to compensate for in their daily service. The simple act of holding together two separate components requires a balancing of forces – this is a complex matter often addressed by application of a “safety margin” judged to be sufficient to deal with the unknowns involved.

However, some industries deal with much more life and performance critical situations than others and so the concept of designing for a product lifetime has evolved – in one way to ensure that the specification is adequate, but on the other to time-limit the expectation, and so ensure that proper maintenance is mandated.

Aerospace, automotive and rail industries all follow this design for a specific lifetime philosophy – an approach rarely used elsewhere – and sometimes this leads to over specification in products which do not need it. This over specification is often a comfort issue, as a sort of safety margin which often makes the custom spec prohibitively expensive if not actually impractical. Over specification is a significant potential problem in the fastener industry.

This generally occurs in applications where there are issues of weight and space but where cost is secondary because of the safety critical nature of the situation. However sometimes given a minimum lifetime expectancy there can be a tendency to “play it safe” and add a safety margin on top of a safety margin, leading to gross over specification, e.g. going up one or two sizes with consequent weight and space implications. Calling for an exotic and expensive alloy where a lower-cost high-grade treated steel would be more appropriate. Over specifying one fastener may not be a problem but over specifying thousands can make a big difference overall.

Design for a specific lifetime is often a highly skilled art of combining knowledge from different areas, e.g. specific performance of the fastener, effect of varying material, options for head types and the stress they involve, stresses inbuilt into the fastener from its manufacturing process or treatment – a solution which can be achieved in concert with a fastener specialist such as Challenge Europe. Contact us here to discuss.

Machine Screws - Challenge Europe discuss what you would use these products for

Machine screws are used almost everywhere! They are ubiquitous in assembly roles world-wide, especially for fixing accessories to castings, fixing castings together, often with nuts – fixing covers in place – from marine situations to aerospace, packaging to electronics.

The materials choice begins with low-grade steel for general purpose on up to high-force situations requiring high-grade steel, elsewhere calling for brass or copper for electrical conductivity, then covering corrosive environments where a stainless steel is needed – even to very high temperature or extremely aggressive environments which may need exotic alloys such as Hastelloy, Elgiloy, Titanium etc.

Typical issues include vibration loosening but this is now reliably addressed by a range of friction-based or washer-type solutions. However, significant care is needed where electro-galvanic action may be envisaged, i.e. where a mix of different materials is envisaged with conflicting electro potential.

The basic format of threaded shank and load-spreading head is capable of extensive adaptation with choices of thread form – although typically these will be an ISO Metric specification. Screw heads however are subject to a very wide range of shapes and design concepts to reduce vibration loosening, facilitate automatic installation, resist vandalism/unauthorised removal, or to create a smoother, more easily cleaned surface, e.g. in the food industry, or to facilitate especially high torque settings, such as may be required in high-performance industries such as aerospace or automotive applications.

Contact the team at Challenge Europe for further information, pricing, delivery etc.

Challenge Europe – ex-stock threaded fasteners for challenging times

At Challenge Europe we have always had a belief that “you can’t sell from an empty basket” and so have had a long-term policy of stocking heavily to ensure we are able to support changes in customer demand.

Therefore, we are pleased to announce that we have good stocks of threaded fasteners so that customers can be assured of robust supply. Of course, this is especially important at this time of general lock-down when it may prove difficult to access many existing channels – and will be just as important when the locks come off and urgent demand is felt in the recovery phase.

It is already clear that the medical device and associated equipment industries are stretched producing many times their usual output of beds, ventilators etc. to note only the headline items. Supply of hardware items such as threaded fasteners – screws, bolts, nuts, washers etc. is being supported by specialist expert stocking distributors like our team here at Challenge Europe who invite any company experiencing supply difficulties on these items, to contact us for an urgent service.

CAD auto specification problems - Challenge Europe

Here at Challenge Europe we come across the risks of excessive reliance on the automatic specification selection feature in many CAD systems at the design stage. These systems match physical dimensions but frequently neglect the materials or stock availability. This is also the case where, for example, a standardised component is requested, but in a material not covered by that standard. This focuses on the need to consult a specialist fastener supplier, especially regarding subcontract assemblies, since it may be that they cannot actually comply with the original drawing. In turn this has a major time implication in getting changes made when compliance is impossible.

A good example is a case where it was found necessary to take a superior product and downgrade it at extra cost, e.g. a washer to a certain specification, custom specified with a wide manufacturing tolerance where actually a normal spec washer would have been suitable but not meet the spec. The solution was to take standard washers and drill them out at extra cost. Especially where small quantities are concerned, this can be a major issue.

The solution has been found to lie in developing trusted supplier relationships where consultation at an early stage can bring these issues to light. Not only will such a supplier have an extensive knowledge of materials and finishes – they will also be in a position to advise on stock availability and alternative ways of meeting custom requirements. For example, it may not be necessary to custom produce from scratch where a standard item with treatment or other adaptation may be suitable, more readily available and cheaper.

Contact us for help with your specification issues.

 

Challenge Europe - specialist guidance re screw materials and finishes an important factor in successful applications

The team here at Challenge Europe are used to dealing with questions of specification regarding materials and finishes of threaded fasteners. This preferably occurs early in the process of defining new assemblies, but may equally be of value at service or repair.

A good example is one where black stainless steel screws were specified using a treatment involving oil, however the retained oil was a significant problem in that it contaminated the substrate and substantially marred the appearance of the final assembly. It subsequently turned out that stainless steel was not necessary and that it was perfectly satisfactory to use normal steel with a different blackening process not requiring an oil – with absolutely no detriment to the application.

In truth, screws and nuts may be produced in so many materials and alloys from mild steel, high tensile steels, stainless steels, brass, nylon, copper, titanium, duplex stainless steels, exotics such as Inconel, Incoloy, Monel, Hastelloy, Zirconium, Molybdenum, Tantalum, Waspaloy, Tungsten, Silicon Bronze, Aluminium, Ferralium, Polyoxymethylene and even Fibreglass or glass reinforced plastics. So, it is not surprising that the selection may be very confusing and potentially problematic, especially when overlain with the further multiplicity of additional finishes available.

Typically, these finishes are most applicable to steels because of their ability to change the properties of screws made from this low-cost material. Primarily aimed at improving corrosion resistance or changing appearance, the most common include zinc, in various forms, occasionally cadmium, also black japanned, chemical black, chrome, electro brass, copper, stayblack or powder coating. Chromate conversion coatings are often used as part of the plating process to passivate the coated surface which enhances corrosion protection and can add a decorative effect in the cases of zinc & yellow and zinc & black. Using which substrate and which finish can be simplified with experienced advice available from a specialist fastener supplier. Contact us here.

Corona virus update

The present situation is a challenge for all of us and it is interesting to see that many companies are stocking up as a precaution – but also as an act of faith that things will get better soon and in the belief that we will all need stock to get the industrial manufacturing machine back up to speed. Here at Challenge Europe we are looking after our staff and our customers ensuring both personal health and the health of our mutual businesses with safe working practices both internally and for delivery at customer sites. We are pleased that we have been able to make arrangements to ensure continuity of supply and service so that our customers continue to be fully supported while the situation lasts.

Contact us to discuss your fastener requirements at this time.

Challenge Europe machine screws future

Machine Screws represent a technology that is now conventional, so that here at Challenge Europe we believe it is interesting to ask “what is their future?”

We have already seen many developments in drives/head configurations for automated production such as Hex drives and other socket screws, leading on to the more modern Phillips, Pozi and star drives, e.g. TORX, developed with a view to self-centring so that they will sustain torque loadings of automatic drives and with the further aim of being self-aligning when inserted.

We already have in the market an extensive selection of different thread pitches/multiple thread screws – custom screws – many diameters and head styles. Including threads for different materials such as steel, soft metals, plastics, zinc die castings, aluminium castings and so on.

More sophisticated driver forms can now be readily produced with advanced production machinery, leading to a great variety of head forms for differing purposes, e.g. wafer heads – thin and large diameter to spread the load over the substrate, which may be a thin sheet or soft material.

Other common forms include Narrow/small dia heads for confined spaces, Dome heads for aesthetics, Countersunk heads for smooth surfaces, Vandal-resistant heads for security, Integral washers, Pre-assembled sealing washers, Load spreading heads and Anti-vibration, e.g. serrated flanges.

A major trend in recent years has been the “right to repair” movement, from the USA to Scandinavia and  is something that the fastener industry has supported, perhaps inadvertently, throughout the industrial revolution to the present day. Mechanical fixings have always inherently provided the option to disassemble and repair as opposed to bonded assemblies which are virtually unrepairable.

Mechanical fasteners in one form or another have been in existence almost from the cave man days as a system that is available at low cost to anyone with only simple tools. Latterly developments have enabled them to be used successfully in most types of assembly environments and at the same time satisfy the requirements of safety, quality and cost. They continue to be a simple solution to assembly problems providing a system of positive connection with low risk, which can be easily disassembled. They have no thickness limitation, are not environmentally sensitive and provide through-thickness reinforcement, with low sensitivity to peel stresses and have no major residual stress problems.

Above all they are simple – joint configuration is simple, manufacturing processes are simple, inspection is simple and maintenance is simple. Simplicity can be a major advantage in most applications and continues to be so in aiding users to extend the life of their equipment. The whole point of right to repair is to cut through the “design to scrap culture” and the expensive “return to manufacturer” policies that go with it.

New EU regulations take the lead on this requiring that from 2021 appliances will need to be both longer lasting and with spare parts available for 10 years. The point being that right to repair seeks to reverse the way that repairs have been taken out of the hands of the user in order to enforce more expensive solutions provided by the manufacturer. The philosophy is that it should be possible for consumers to repair cheaply – from washing machines to tractors – from software to mechanics – and threaded fasteners are a significant contribution to this approach.

Simplicity however does not mean they are incapable of sophistication with major advantages over chemical fastening adhesives. For example, threaded fasteners are commonly used with a torque adjustable closure force permitting pre-loading of the joint to allow it to adapt to variable loads from engines to couplings.

Similarly, the structural integrity, strength and security of mechanical fasteners can be designed to encompass the needs of vandal-resistance, to accommodate the extreme loads of vandal attack and to resist tools. In our drive for the new it is easy to forget the advantages of the old technologies.

With a mechanical fastener, when it is fixed, it is fixed and with a little thought it stays fixed. You can have confidence in what you feel when you fit it and what you see when you inspect it.

Given all these benefits and the driving forces of reducing lifetime cost, we foresee a strong trend of  continuing evolution to meet major market requirements focused on:

  • Better production technologies leading to better quality, greater accuracy, cleaner execution, reduced wastage, lower cost.
  • Higher performance through use of higher spec materials, better finishes, superior insertion and drive capabilities, coupled with development of new thread forms to suit different materials and applications.

As discussed elsewhere, new thread forms are in development, but do not seem to have mass market utility as yet.

This has been the story of machine screws so far and we can only see it continuing as new industries of personal transit, renewable energy and recycling continue to develop new requirements with ever-lower energy use.

Clearly the threaded fastener industry continues to be vibrant with evolutionary growth based on their simple functionality at low cost.

Challenge Europe discuss the future for Imperial and Metric Screws

Sorting out the multiplicity of screw thread designs has been such a big issue for so long that there are lots of guides to give approximate conversions, although naturally there are no actual like-for-like equivalents. Our team here at Challenge Europe recently discussed a little history and some future-gazing.

Imperial threads – as it may be expected come out of the ins./feet standard developed in the blossoming of the industrial revolution when Imperial meant British Empire and then into the dynamic drive for mass production seen in the USA. These imperial threads were in their heyday at the end of that era which was approximately in the early part of the 20th century. When the Empire broke up under the stresses of two world wars and the rise of international power blocs together with demands for independence they continued in general use since the momentum of these newly grown industries carried them forward. Metric on the other hand comes from the millimetre/centimetre measurement system so popularised by Napoleon in the continental European theatre and subsequently established in the rebuilding and regrowth of the European manufacturing industries after the devastation of the wars that took place there.

They are not mutually compatible of course but may have approximate size replacements. The two standards essentially run alongside each other with metric (ISO) being the one that is replacing imperial across the world – it is the defacto global standard.

Consequently, metric screws are more readily available, e.g. ex-stock, more standard sizes, more easily sourced, more development in new products, more widely used and continuing to replace imperial globally on new projects. Challenge Europe are one of the few specialists who stock both standards in depth.

Increasingly tool kits are solely metric – although even today new spanners, taps and dies are available for Whitworth and BA – but are expensive so that they are often sourced by hobbyists and renovators as second hand items at auctions and car boot sales.

Since Imperial standards derive from the early days of the industrial revolution and industries like ship building and armaments that were important to the days of Empire and grew immensely at that time.

The first national standard was Whitworth – devised and specified by Joseph Whitworth in 1841. Followed by William Sellers who developed the Sellers thread of 1868 later developed into American Standard coarse and fine.

Well known to instrument and model makers is the British Association screw thread standard – known as BA these are small screws with the largest being OBA = 6mm dia. There continues to be a low level demand  for older applications, e.g. old instruments – or for rebuilding of older vehicles.

Many countries have run both types alongside each other but all are in the process of moving to ISO metric standards if they have not already done so. The USA has probably held out longest due to the inertia of its huge market, but globalisation has led to sourcing of cheaper metric products for mass production and this has driven the conversion. The US/American market is therefore becoming more restricted – imperial products used to be the mainstay of general sales in the US, but not so now as US customers are more comfortable with metric specs. Availability of metric equipment in the US has now completely overtaken imperial screws in a relatively short time – roughly coinciding with the rise of Chinese manufacturing as the component supplier to the world.

New thread design development continues as specialist companies and engineering enthusiasts seek to explore niche areas, for example, “total surface contact” and bone screw fasteners – which may one day find application outside the medical/surgical field.

One particularly interesting arena is that of alignment correction whereby a misaligned screw will self-correct and pull itself back to its true axis.

Further developments are aimed at improving the performance of screws subjected to transverse loads which can lead to self-loosening or fatigue failure.

However, in the mass manufacturing market we do not at present see any further new thread designs on the horizon since metric forms seem to have adapted well to all general requirements. Elsewhere, other designs of fastener have been extensively developed from push-fit plumbing connectors to pop-in electrical and electronic fittings and this approach to specialist fastenings has very much taken off as a new way of dealing with often completely new problems.

While the transition from “old” to “new” thread forms is almost complete and many threaded fasteners have simply not been specified where they might previously – because now more cost-efficient fasteners of specialised design are available. However, it does seem that pockets of demand for imperial threads will continue for a long time yet.

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