SPIDA FIXINGS CONFORM TO THE HIGHEST STANDARDS OF ANY FASTENER.
Spida Fixings are the result of years of process improvement to achieve manufacturing expertise.
Every fixing follows a strict production process that ensure quality and reliability. Our quality checks are conducted on every batch that goes out.
Spida Fixings have a unique patented construction. From the materials to the manufacture process, every effort has been made to increase strength. With the advances we have made in bond strength and stress dissipation our fixings need to be capable of handling the greater loads that can now be applied. Our patented design features allow more load to be passed through from the fastener to the base.
Our fastener heads are circumferentially welded to the rear of the base, vastly improving tensional strength. The base is the optimal thickness to withstand the high loads our fixings are designed for.
We use the best possible materials for our fasteners.
Our heat treated high tensile carbon steel products are made from (20MnB4/CR4) or marine grade stainless steel (316L). This is a premium steel ideal for fasteners as characterised by its consistent mechanical properties, homogeneous structure, minimal dimensional tolerances and it’s ease of use in cold forging and welding without cracking or necking. The bases of our carbon steel fasteners are made from CR4 which is ideal for progression pressing.
We also offer marine grade 316L stainless steel fixings. 316L contains additional molybdenum providing enhanced resistance to corrosion and it’s low carbon content offers additional resistant to grain boundary carbide precipitation. Additionally its non magnetic austenitic structure gives excellent toughness particularly at cryogenic temperatures.
Our carbon reinforced thermoplastic fixings are made from polyamide-imide, a lightweight thermoplastic that is extremely high strength, and has a high resistance to heat and chemical degradation. This material is so high performance that they can even replace metal fixings where lightweighting or (military) stealth capability is desired.
Our stainless steel fixings are passivated to improve their corrosion resistance.
Our mild steel fixings have automotive standard Zinc nickel plating which offers hardness value 3 times higher than zinc plating alone. Plus
8 micron thick layer that provides corrosion resistance of 240hrs of salt spray resistance to white rust (corrosion of the Zinc plating) and 720hrs to red rust (corrosion of the Iron itself).
Our passivation and plating is done by the top suppliers in Europe to ensure that we achieve the highest standard finish for our fixings.
We spent 2 years designing and engineering the perfect fixing. By using finite element analysis (or FEA for short) we could simulate how our designs would respond to real world stresses. Prototypes were then subject to extensive testing in our custom build test rig and finally in real life applications.
Designing out the weak points
The weakest point of any male threaded fastener is just below the last thread. Our studs compensate for this by retaining as much material as possible at this point and gently tapering into the base. The optimised grainflow in this area also improves its strength. These factors allow more load to be passed through to the base.
We cold forge our fasteners and progression press our bases which enhances the metallic grainflow to provide superior strength. We also roll the threads onto our fasteners (rather than cutting, chasing or grinding them) which further improves the grainflow.
A better weld
The larger 35mm and 53mm Spida bases are fed onto the stud head and then autogenously welded from behind ensuring that as much of the two parts as possible are joined. This makes it impossible to pull the stud off the base or push it through, which means that our fixings can withstand forces up to the ISO breaking point of the thread; not something you can be sure of with other welded together studs.
Our proprietary Admax treatment makes the metal denser, harder and therefore stronger and also reduces fatigue crack nucleation.
From our rolled threads to our advanced welding machines our manufacturing processes and quality checks ensure that every fixing attains a high degree of accuracy. This not only allows you to construct products with more precision but it also reduces the chance of fixing failure by reducing point loading and uneven bonding.
Bond strength - Keeping the fixing in place
Bond Spida on with adhesive. Now stronger than ever.
Bonding a fixing using epoxy adhesive is one of the most common installation methods. You simply apply adhesive to the base and positions it in place. With Spida Fixings not only is it possible to use this method for holding accessory structures (e.g. wiring) in place; it is now possible to use an epoxy bonded Spida Fixing to secure even the most structurally important components that must withstand high forces (e.g. seating). To achieve this we went back to drawing board and redesigned the standard bonded fastener into something that now has over 50% greater bond strength.
Moulding Spida into the structure. Bonded from all sides.
An alternative installation method is to mould a Spida into a structure (using hand layup, vacuum moulding, injection moulding etc). This saves manufacturing time and increases structural integrity. Our mouldable Spida Fixings have the perfect all over surface to achieve a high strength bond in your mould. And you can be sure that your Spida can resist rotational forces with our patented castellations on the base.
Anti torsion - 'castellations'
The circumference of the Spida base has small semi-circular notches in it, these patented notches are called ‘castellations'. The adhesive or resin around these castellations improves the torsional, peel and cleavage strength of the fastener.
The edge of the base is where mechanical advantage is greatest and therefore the best location for this anti-torsion feature.
As well as improving torsional resistance the castellations improve the rheology of adhesive as it protrudes from the edge of the base which also improves it's peel and cleavage strength.
When a flat based fixing is bonded there is no control over depth of adhesive. Whether installing by hand or using a jig there is a natural tendency for installers to press ‘hard’ when positioning a fixing. This results in adhesive being squashed out from under the base.
Adhesives such as epoxy have an optimal 'bond line depth’ i.e. depth of adhesive between the substrate and base of the fastener.
Our bondable Spida fixings have a dome shaped base. We call this patented feature the 'exothermic chamber’. This controls the depth of adhesive. Achieving the desired bond line depth allows the adhesive to heat up and undergo a complete exothermic reaction, this creates a stronger bond.
Note that for moulding and welding we also sell flat based fixings.
When bonding a flat based fixing the adhesive that squashes out the edge forms a ridge. In perforated fasteners adhesive also pours through the perforations forming spaghetti like pillars. These formations can cause air voids if laminated over. The obtuse angles at the edges of the formations are highly prone to stress lines. The waste adhesive increases cost and weight. The spaghetti shaped pillars give the impression of ‘adhesive rivets’, however they in fact form resin rich and brittle hotspots which have limited tensile advantage and can even cause localised thermal damage to the substrate.
The exothermic chamber provides the optimal adhesive rheology during installation by providing a space for the adhesive to spread evenly into.
If a Spida fixing is accidentally overloaded with adhesive this can be more easily wiped away from the edges as the fixing is not ‘floating’ on a pool of adhesive like with flat based fixings.
Patented concave base
Spida Fixings are designed to hold in place a threaded fastener that can be loaded up to its ISO breaking point without damaging the fastener, bond, substrate or the component connected to the fixing.
The 'parabolic elasticity' of Spida’s patented concave shaped base means that forces are not 'point loaded' into the centre of the fastener, instead they are dissipated across the entire base and beyond.
Stresses in the centre of the base are attenuated because there is space for more adhesive in the centre. Optimal tensile strength is also provided by a parabolic base, as this is the shape that a flat plate forms naturally when pulled in the centre.
This prevents premature adhesive or cohesive failure in the centre of the base and reduces the forces applied to the fastener, substrate and connected component, which means you can use less fasteners for the same job. Just think what that means for your product’s weight, cost and manufacture time.
A balanced footing
Our concave base shape self-levels the fixing by forcing it to land level to the substrate even when loaded with a viscous adhesive. This is because the concavity retains a space for the adhesive whilst the edge of the base levels the fixing. This is one reason why we recommend our concave bases for exothermic adhesives such as epoxy. Retaining a similar level of adhesive under a flat base would make it difficult to ensure perpendicularity. The slightest deviation and the adhesive may not spread out evenly under the base leaving an area with less or zero adhesive, which will weakening the bond. We therefore only recommend our flat bases for welding and non-exothermic adhesives such as acrylics that require a minimal bond line depth of adhesive.
Also, if a concave base is accidentally overloaded with adhesive this can be more easily wiped away from the edges as the fixing is not ‘floating’ on a pool of adhesive like with flat based fixings.
The shape of the base also affects the polymer chains (i.e. molecular structure) in the adhesive. When the adhesive under a flat base is squashed very thin the polymer chains align parallel to the substrate. Our concave bases allow space for more polymer chains to form at right angles to the substrate helping it to resist tensile, peel, shear and cleavage loads.
A real life example of polymer chain alignment is seen in a plastic shopping bag. Due to the way the bag is made the polymer chains are aligned in the direction of the handle, this makes it strong enough to hold by the handle but weak if you try to stretch the bag sideways (perpendicular to the polymer chains). With a fixing that needs to resist forces from multiple directions it is important that polymer chain alignment is avoided. This is why we only recommend our flat based fixings for welding and specialist adhesives such as acrylic that require minimal bond line depth.
Curing adhesive bonded fixings
We offer a range of fixings for different applications. Our concave bases are suitable for most applications including bonding with epoxy adhesives.
Whether installing a bonded fixing by hand or using a jig there is a natural tendency for installers to press ‘hard’ when positioning it. This results in adhesive being squashed out from under the base leaving only a thin layer. Our research has shown that when using an exothermic adhesive (i.e. adhesives that cure by creating their own heat when mixed) such as epoxy, this thin layer does not usually reach ‘peak exotherm’ (i.e. optimal temperature) under real life conditions and therefore the bond is not fully cured. This is why we developed Spida fixings with concave bases that retain the optimal depth of adhesive under them.
Saving weight, cost and manufacture time...
Spida Fixings are designed to hold in place a threaded fastener that can be loaded up to its ISO breaking point without damaging the fastener, bond or substrate. The parabolic elasticity of Spida’s patented dome shaped base helps to dissipate stress across the entire base of the fastener and beyond. This means you can use less fasteners. Just think what that means for your product’s weight, cost and manufacture time.
Bondable fixings. Dissipating stress through the base
Our bondable Spida fixings are designed to dissipate stress over a larger area to reduce point loading. This means they can support higher loads without damaging the fixing, the substrate or the component connected to the fixing.
If the underside of a bonded fixing is flat, there is a more localised deformation because more load goes through the centre of the fastener where the thread connects to the base. This can cause premature adhesive or cohesive failure in the centre of the base; break the fixing, damaging the substrate and pass excessive stresses onto the connected component.
The parabolic elasticity of bonded Spida fixings helps to dissipate compressive stresses over the entire base and beyond. Stresses in the centre of the base are attenuated because there is space for more adhesive in the centre. Optimal tensile strength is also provided by a dome shaped base, as this is the shape that a flat plate forms naturally when pulled in the centre.
Mouldable fixings. Dissipating stress in every direction
Mould a Spida fixing with a large base and Admax into your product for the ultimate in stress dissipation. Stresses are passed deep into the structure making them highly dissipated and attenuated.
What does this mean for you?
By dissipating stress more effectively our fixings are able to handle higher loads. This means that manufacturers can use less / smaller fixings, saving weight, installation time and cost.
Alternatively it means that you can use Spida fixings for applications that you never thought possible before.
ACHIEVES AN UNBEATABLE BOND
Admax is our proprietary treatment that has been specially developed to increase the bond strength of Spida fixings. Unlike the fine matte finish that is found on some other fixings, Admax creates surface deformation to depths of around 20 microns. That is up to FIVE TIMES more than other fixing treatments. This increases Spida’s surface area, surface energy and wicking properties, dramatically increasing bond strength.
Our advanced Admax technology not only deforms the surface but also creates microscopic undercuts, significantly increasing the mechanical strength of the bond. On our carbon steel fixings we use an advanced electroplating technique to protect and further increase the size of the undercuts.
Reduced contact with substrate
Without Admax the base of a fixing could make contact with the substrate. Admax reduced the potential contact area from about 1cm2 down to a few microns. This is because only the microscopic 'peaks’ of the undulations will make contact with the substrate. The rest of the surface will fill with adhesive further increasing the strength of the bond.
Minimum bondline thickness
The 20 micron deep undulations ensure a minimum bond-line thickness around the edge of concave bases and the bottom of flat based fixings.
Reduction in air voids
The Admax surface treatment is designed in such a way that helps the adhesive spread across the surface of fastener without leaving air voids.
Not just a surface treatment
Admax treatment makes the metal denser, harder and therefore stronger and also reduces fatigue crack nucleation.