wire rope load calculator brands

Wire rope is also known by many other names, such as: wire, multi-strand wire, flexible wire, cable, cord, steelcord, etc. but it is essentially a collection of small filaments wound around each other in a manner that largely retains its shape when bent, crushed and/or tensioned.

It is a system for significantly increasing the strength and flexibility of steel wire and is used in almost every important application we see around us. For example: suspension bridges, tyres, brake and accelerator cables (in cars), high-pressure flexible pipes, lifting and rigging cables, electrical conductors, etc. and it comes in many different forms. Fig 2 shows just a very small sample of available designs.

With minor variations, the generally accepted method for designating a wire rope construction in the industry is by describing it numerically. For example:

Whilst "IWRC" wire ropes offer a slightly greater tensile capacity (≈7%) than those with fabric or polymer fillers, the additional strength does not come from the tensile capacity of the core filaments but from improved dimensional stability under load. And whilst they are also much more resistant to crushing, they are stiffer than fibre core ropes and therefore not recommended for applications where tension occurs under bending.

Warrington (Fig 1) is a parallel lay construction with an outer layer comprising wires of alternating large and small diameters, each outer layer having twice the number of wires as the layer immediately beneath. The benefit of this design is to increase packing and therefore strength density, however, unless the different diameter filaments are of the same strength (unlikely), this construction is limited by the strength of the weakest filaments.

Seale (Figs 1 & 2 6x36) is also a parallel lay construction but with the same number of wires in each wire layer. All the wires in any layer are the same diameter. This is an alternative to the Warrington construction, with similar benefits and disadvantages.

Regular lay constructions are used much more widely (than Lang lay) because they have excellent structural stability and less tendency to unwrap under tension (see Rotating vs Non-Rotating below). However, because it has a knobbly (undulating) surface it will wear both itself and any surface over which it is run much more quickly than Lang lay wire rope.

Lang lay constructions have a flatter surface than regular lay constructions giving them better resistance to wear and bending fatigue, especially when made from flattened (elliptical) filaments. They are, however, much less structurally stable and subject to birdcaging if the wire rope is over-bent or twisted against its wrapped direction.

"Regular Lay", multi-strand constructions are normally subject to slightly less rotation under tension (than Lang lay) due to the opposite helical direction of the filaments (within the strands) and the strands (within the rope), however, you can improve their rotation characteristics still further by;

Fillers (Fig 2) may be fabric, polymer or even smaller diameter filaments (e.g. 6x36). Whilst they contribute little to the tensile strength of wire rope, they can significantly; improve performance under bending (fabric and polymer cores only), reduce axial growth, reduce rotation in rotation-resistant constructions, improve structural stability and increase fatigue life.

This filler material should not be included in strength (tensile capacity) calculations, but must be included in those for axial stiffness (extension). If it is ignored, your calculations will reveal excessive extension as the wire rope collapses.

Suspension bridges tend to be constructed from densely packed, single strand plain "Wire Rope" constructions using large diameter galvanised filaments. Little heed is paid to rotational resistance as strength is paramount and once tensioned, they should remain in that loading condition for their design life.

Lifting & winching normally require wire ropes of good flexibility and fatigue resistance. Therefore they tend to be similar to 6x36 but with fibre core instead of the IWRC in Fig 2

Remote operating cables such as hand-brakes and accelerators on cars normally only work in tension so they need to be strong but not necessarily stiff (as they are fully contained in reinforced outer sheaths). These tend to be manufactured from large diameter "TyreCord" or small diameter single-strand "Wire Rope".

Wire rope does not obey Hooke"s law. Therefore, you cannot accurately predict how much it will stretch for any specified force. This unpredictability applies to any section removed from the same manufactured length of cord and even between cords produced to the same specification but by different manufacturers.

CalQlata has decided that the accuracy of axial stiffness (EA) of wire rope falls outside its own levels of acceptability and therefore does not include it in the wire rope calculator. The extension calculated in the Wire Rope calculator (δLᵀ) is based upon the effect of axial tension on packing density. It is therefore important that core material is not ignored when using the calculator to evaluate this characteristic.

Wire rope does not obey Hooke"s law. Therefore, you cannot accurately predict how much it will twist for any specified torque. This unpredictability applies to any section removed from the same manufactured length of cord and even between cords produced to the same specification but by different manufacturers.

CalQlata has decided that the accuracy of torsional stiffness (GJ) of wire rope falls outside its own levels of acceptability and therefore does not include it in the wire rope calculator.

1) No wire rope calculator, whether dedicated or generic, will accurately predict the properties of any single construction under a wide range of loading conditions

2) No wire rope calculator, whether dedicated or generic, will accurately predict any single property for a range of constructions under a wide range of loading conditions

The only wire rope that can be reliably analysed is that which is used for suspension bridges, because; it comprises a single strand, is very densely packed, has negligible twist, contains filaments of only one diameter, is never subjected to minimum bending and every filament is individually tensioned.

There is a very good reason why manufacturers do not present calculated performance data for construction or design proposals, because even they cannot accurately predict such properties and quite rightly rely on, and publish, test data.

During his time working in the industry, the wire rope calculator"s creator has seen, created and abandoned numerous mathematical models both simple and complex. He has gradually developed his own simplified calculation principle based upon his own experience that still provides him with consistently reliable results of reasonable accuracy.

The purpose of CalQlata"s wire rope calculator is to provide its user with the ability to obtain a reasonable approximation for a generic construction, after which, accurate test data should be sought from the manufacturer for the user"s preferred construction.

The calculation principle in the wire rope calculator is based upon changes in the properties of the wire rope that occur with variations in packing density under tension

Bearing in mind the above limitations CalQlata can provide the following assistance when generating (manipulating) the wire rope calculator"s input data and interpreting its output

Alternatively, for wire rope with multiple filament diameters, you need to find an equivalent diameter with the following proviso; you must enter the minimum filament yield stress (SMYS)

It is expected that apart from fillers, all the material in the wire rope will be identical and therefore have the same density, i.e. using different materials will result in less than "best" performance. However, if such a construction is proposed, you can calculate an equivalent density as follows:

It is expected that apart from fillers, all the material in the wire rope will be identical and therefore have the same tensile modulus, i.e. using different materials will result in less than "best" performance. However, if such a construction is proposed, you should enter the highest tensile modulus.

The wire rope calculator simply adds together the total area of all the filaments and multiplies them by the SMYS entered, which represents a theoretical maximum breaking load that would exist if this load is equally shared across all of the filaments and the lay angles have been arranged to eliminate localised (point) loads between adjacent filaments.

If the wire rope has been properly constructed it is likely that its actual break load will be greater than 80% of this theoretical value. However, given the vagaries of wire rope construction, the actual break load can vary considerably dependent upon a number of factors. CalQlata suggest that the following factors may be used to define the anticipated break load of any given construction:

The axial stiffness and strain under load will be affected by this value, hence the reason why the most reliable (predictable) constructions tend to be minimum [number of] strands and single filament diameter. The Warrington and Seale constructions and combinations thereof tend to provide the highest packing density (but lowest flexibility) and there is little to be gained from using these constructions in more than single stranded wire rope as the benefit of high-packing density will be lost with no gain in flexibility.

The anticipated second moment of area of the wire rope at tension "T" due to deformation but insignificant flattening as it is assumed the wire rope will be bent over a formed (shaped) sheave or roller.

The anticipated tensile modulus of the wire rope at tension "T" due to deformation but insignificant flattening as it is assumed the wire rope will be bent over a formed (shaped) sheave or roller.

It is not advisable to induce this bend radius in operation due to uncertainties associated with wire rope construction, especially for dynamic applications. CalQlata suggests that a similar approach to that used for the break load (Fb) above also be applied here, i.e.:

A change in diameter will occur in all wire rope, irrespective of construction, until packing density has reached a limiting value. The value provided in the wire rope calculator is that which would be expected if the construction remains intact at the applied tension "T"

Unreliability of this value increases with complexity in wire rope due to its longitudinal variability and the increased likelihood of premature failure.

The accuracy of this data will range from about ±1% for wire rope with a single strand and a single filament diameter, up to about ±15% for constructions of similar complexity to OTR cord

A change in length of any wire rope will occur due to the fact that the packing density increases with tension. This is not, however, a linear relationship.

This can be an unreliable value as illustrated by tests carried out (by the author) on two pieces of wire rope supplied by the same well-known manufacturer both of which were cut from the same length, varied in tensile capacity by only 1.5%, but the tensile modulus (and strain at break) varied by 34%. Whilst this was an extreme case, significant variations have been seen in wire rope manufactured by a number of manufacturers.

Whilst the wire rope calculator does not calculate axial stiffness (see Calculation Limitations 9) above), CalQlata can suggest the following rule-of-thumb that will provide reasonable results for most constructions at the applied tension "T":

Where: θ = the "absolute" sum of the average filament lay angle and the average strand lay angle⁽²⁾. Note; the angle of twist (θ) will reduce as tension approaches break load.

Whilst the wire rope calculator does not calculate bending stiffness (see Calculation Limitations 8) above), CalQlata can suggest the following rule-of-thumb that will provide reasonable results for most constructions at the applied tension "T":

Low complexity means single strand and single wire diameter. Medium complexity means multi-strand and single wire diameter. High complexity means multi-strand and multiple wire diameters.

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Block Division, Inc., has established through an accredited testing laboratory the capacity at which our products may be safely used. This may be defined as the safe working load limit, a chain or cable rope pulley block load calculation, or a force calculator.  The safe working load limit (mechanical advantage) is the maximum load in pounds which should ever be applied, and when the load is applied uniformly and in direct tension to a straight segment of wire rope.  By changing the degree of angle between lead and load angle, this also affects the stress on the block. The stress on the eye may be decreased by increasing the angle between the load and the lead angle.  See chart 1 and illustration below.

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Enter the diameter of the wire rope, in mm, into the calculator to determine the safe working load (SWL). This calculator is for education purposes only, follow manufacturing guidelines for true SWL values.

A safe working load of a wire rope is a measure of the total load or weight that a wire rope can safely support during operation. Values greater than the SWL could result in a failure of the rope.

The end fittings at the load will see the same force as the sling connected to it, and they must also be adequate for their intended use. Please consult Northern Strands order desk for capacities with the use of hardware, or the addition of a top Masterlink.

PFEIFER DRAKO wants to point out that the suitability and usability of the recommended PFEIFER DRAKO products also depend on the suitability of all other components of the elevator for this projected installation and its specifications accordingly. The determined data therefore has to be regarded as a suggestion not as a final elevator design calculation! It is imperatively necessary to do a final calculation regarding all relevant factors of influence. The calculated expected number of trips is the result of the influences of chosen elevator configuration on the chosen rope type. The basis for this calculation is the statistical data and the rope lifetime equations for running steel wire from taken from K. Feyrer, Wire Ropes, Springer Verlag 2018. The selectable rope types have the according PFEIFER DRAKO brand name. The calculation does not include a quality assessment of the products. The interaction of the chosen rope drive and the rope forces, caused by the applied masses but also further factors of the elevator (i.e. acceleration, rope force differences, friction) and the chosen rope construction is evaluated by means of an approved theoretical basis. Exact and smooth rope installation, good rope tensioning and sufficient re-lubrication must be guaranteed. The calculated data is not subject to be claimed as a legally binding statement for the end-user. It is to be seen as an indication based on the above described theoretical basis, which number of trips can theoretically be expected with the given configurations.

VERTICAL, or straight, attachment is simply using a sling to connect a lifting hook to a load. Full rated lifting capacity of the sling may be utilized, but must not be exceeded. A tagline should be used to prevent load rotation, which may damage a sling.

When two or more slings are attached to the same lifting hook, the total hitch becomes, in effect, a lifting bridle, and the load is distributed equally among the individual slings.

CHOKERhitches reduce lifting capability of a sling since this method of rigging affects ability of the wire rope components to adjust during the lift. A choker is used when the load will not be seriously damaged by the sling body — or the sling damaged by the load, and when the lift requires the sling to snug up against the load.

The diameter of the bend where the sling contacts the load should keep the point of choke against the sling BODY — never against a splice or the base of the eye. When a choke is used at an angle of less than 120 degrees (see next page), the sling-rated capacity must be adjusted downward.

A choker hitch should be pulled tight before a lift is made — NOT PULLED DOWN DURING THE LIFT. It is also dangerous to use only one choker hitch to lift a load which might shift or slide out of the choke.

As the included angle between the legs of a sling decreases, the load on each leg increases. The effect is the same whether a single sling is used as a basket or two slings are used with each in a straight pull, as with a 2-legged bridle.

Anytime pull is exerted at an angle on a leg—or legs—of a sling, the load per leg can be determined by using the data in the table above. Proceed as follows to calculate this load—and determine the rated capacity required of the sling, or slings, needed for a lift.First, divide the total load to be lifted by the number of legs to be used. This provides the load per leg if the lift were being made with all legs being vertically.

Then MULTIPLY the load per leg (as computed above) by the Load Factor for the leg angle being used (from the table at the bottom) – to compute the ACTUAL LOAD on each leg for this lift and angle. THE ACTUAL LOAD MUST NOT EXCEED THE RATED SLING CAPACITY.

Thus, in the above drawing (sling angle at 60°): 1000 ÷ 2 = 500 (Load Per Leg if a vertical lift) 500 x 1.154 = 577 lbs. – ACTUAL LOAD on each leg at the 60° included angle being used.

In the above drawing (sling angle of 45°): 1000 ÷ 2 = 500 (Load Per Leg if a vertical lift) 500 x 1.414 = 707 lbs. = ACTUAL LOAD on each leg at the 45° horizontal angle being used.

The horizontal angle of bridles with 3 or more legs is measured the same as the horizontal sling angle of 2-legged hitches. In this case, where a bridle designed with different leg lengths results in horizontal angles, the leg with the smallest horizontal angle will carry the greatest load. Therefore, the smallest horizontal angle is used in calculating actual leg load and evaluating the rated capacity of the sling proposed.

On the other hand, the eye should always be used on a hook or pin with at least the nominal diameter of the rope—since applying the D/d Ratio shows an efficiency loss of approximately 50% when the relationship is less than 1/1.

When rigged as a basket, DIAMETER of the bend where a sling contacts the load can be a limiting factor on sling capacity. Standard D/d ratios— where “D” is the diameter of bend, and “d” the diameter of the rope—are applied to determine efficiency of various sling constructions, as indicated below:Mechanically Spliced, Single-Part Slings: 25 times rope diameter

Whether to use a single-part sling (one made of a single wire rope in the sling body) or a multi-part sling (several ropes in the body) is usually the first decision to make after determining the sling length and capacity for a lift.

The starting point for this decision involves the handling characteristics of the sling more than any other factor. Based on capacity alone, multi-part slings will be more flexible…more easily handled…than single-part slings. The larger the capacity of a sling, the more important this becomes…to the point, it becomes unrealistic to build big capacity slings from single, very large wire ropes.

In the design of the sling, rope engineers must seek a balance between strength-handling characteristics and number of parts…since there is a tendency to lose strength as core parts are added to increase flexibility.

If a load is hanging free, the normal choke angle is approximately 135 degrees. When the angle is less than 135 degrees, an adjustment in the sling-rated capacity must be made. Choker hitches at angles greater than 135 degrees are not recommended since they are unstable.

Extreme care should be taken to determine the angle of choke as accurately as possible. In controlled tests, where the angle was less than 120 degrees, the sling body always failed at the point of choke when pulled to destruction. Allowance for this phenomenon must be made anytime a choker hitch is used to shift, turn or control a load, or when the pull is against the choke in a multi-leg lift.

This is the length of wire rope between splices, sleeves or fittings. Generally, the minimum body length is equal to ten (10) times the sling body diameter. This allows approximately one and one half (1-1/2) rope lays between splices. For Multi-part slings, the minimum body length between splices is equal to forty (40) times the component rope diameter.

Wire rope strength in the United States is typically shown in tons of 2,000 lbs. The wire rope strength is shown as minimum breaking force (MBF). This is a calculated strength that has been accepted by the wire rope industry. When tested on a tensile machine, a new rope will break at a value equal to- or higher than – the minimum breaking force shown for that rope. The published values apply to new, unused rope. A rope should never operate at – or near- the minimum breaking force. The minimum breaking force of the rope must be divided by the design factor required for the application to determine the maximum load allowed on the rope. During its useful life, a rope loses strength gradually due to natural causes such as surface wear and metal fatigue.

Fatigue resistance involves fatigue of the wire used to make up a rope. To have high fatigue resistance, wires must be capable of bending repeatedly under stress – for example, as a loaded rope passes over a sheave during operation. Increased fatigues resistance is achieved in a rope design by using a large number of wires. It involves both the wire properties and rope construction. In general, a rope made of many wires will have greater fatigue resistance than a same – size rope made of fewer, larger wires because smaller wires have a greater ability to bend as a rope passes over a sheave or around drums. To overcome the effects of fatigue, ropes must never bend over sheaves or drums with a diameter so small as to bend wires excessively. Standard for specific applications contain requirements for minimum sheave and drum sizes. Every rope is subject to metal fatigue from bending stress while in operation, and therefore the rope’s strength gradually diminishes as the rope is used.

Crushing is the effect of external pressure on a rope, which damages it by distorting the cross-section shape of the rope, its strands or core -or all three. Crushing resistance therefore is a rope’s ability to withstand or resist external forces, and is a term generally used to express comparison between ropes. When a rope is damaged by crushing, the wires, strands and core are prevented from moving and adjusting normally during operation. In general, IWRC ropes are more crush

resistant than fiber core ropes. Regular lay ropes are more crush resistant than lang lay ropes. 6-strand ropes have greater crush resistance than 8-strand ropes or 19-strand ropes. Compacted strand ropes are more resistant than standard round-strand ropes.

When a load is placed on a rope, torque is created within the rope as wires and strands try to straighten out. This is normal and the rope is designed to operate with this load-induced torque. However, this torque can cause both single part and multiple part hoisting systems to rotate. Load induced torque can be reduced by specially designed ropes. In standard 6 and 8- strand ropes, the torques produced by the outer strands and the IWRC are in the same direction and add together. In rotation-resistant ropes, the lay of the outer strands is in the opposite direction to the lay of the inner strands, thus the torques produced are in opposite directions and the torques subtract from each other.

Rope strength is a misunderstood metric. One boater will talk about tensile strength, while the other will talk about working load. Both of these are important measurements, and it’s worth learning how to measure and understand them. Each of these measurements has different uses, and here we’re going to give a brief overview of what’s what. Here’s all you need to know about rope strength.

Each type of line, natural fiber, synthetic and wire rope, have different breaking strengths and safe working loads. Natural breaking strength of manila line is the standard against which other lines are compared. Synthetic lines have been assigned “comparison factors” against which they are compared to manila line. The basic breaking strength factor for manila line is found by multiplying the square of the circumference of the line by 900 lbs.

Just being able to calculate breaking strength doesn’t give one a safety margin. The breaking strength formula was developed on the average breaking strength of a new line under laboratory conditions. Without straining the line until it parts, you don’t know if that particular piece of line was above average or below average. For more information, we have discussed the safe working load of ropes made of different materials in this article here.

It’s very important to understand the fundamental differences between the tensile strength of a rope, and a rope’s working load. Both terms refer to rope strength but they’re not the same measurement.

A rope’s tensile strength is the measure of a brand-new rope’s breaking point tested under strict laboratory-controlled conditions. These tests are done by incrementally increasing the load that a rope is expected to carry, until the rope breaks. Rather than adding weight to a line, the test is performed by wrapping the rope around two capstans that slowly turn the rope, adding increasing tension until the rope fails. This test will be repeated on numerous ropes, and an average will be taken. Note that all of these tests will use the ASTM test method D-6268.

The average number will be quoted as the rope’s tensile strength. However, a manufacturer may also test a rope’s minimum tensile strength. This number is often used instead. A rope’s minimum tensile strength is calculated in the same way, but it takes the average strength rating and reduces it by 20%.

A rope’s working load is a different measurement altogether. It’s determined by taking the tensile strength rating and dividing it accordingly, making a figure that’s more in-line with an appropriate maximum load, taking factors such as construction, weave, and rope longevity into the mix as well. A large number of variables will determine the maximum working load of a rope, including the age and condition of the rope too. It’s a complicated equation (as demonstrated above) and if math isn’t your strong point, it’s best left to professionals.

However, if you want to make an educated guess at the recommended working load of a rope, it usually falls between 15% and 25% of the line’s tensile strength rating. It’s a lotlower than you’d think. There are some exceptions, and different construction methods yield different results. For example, a Nylon rope braided with certain fibers may have a stronger working load than a rope twisted out of natural fibers.

For safety purposes, always refer to the information issued by your rope’s manufacturer, and pay close attention to the working load and don’t exceed it. Safety first! Always.

If you’re a regular sailor, climber, or arborist, or just have a keen interest in knot-tying, be warned! Every knot that you tie will reduce your rope’s overall tensile strength. Some knots aren’t particularly damaging, while others can be devastating. A good rule of thumb is to accept the fact that a tied knot will reduce your rope’s tensile strength by around 50%. That’s an extreme figure, sure, but when it comes to hauling critical loads, why take chances?

Knots are unavoidable: they’re useful, practical, and strong. Splices are the same. They both degrade a rope’s strength. They do this because a slight distortion of a rope will cause certain parts of the rope (namely the outer strands) to carry more weight than others (the inner strand). In some cases, the outer strands end up carrying all the weight while the inner strands carry none of it! This isn’t ideal, as you can imagine.

Some knots cause certain fibers to become compressed, and others stretched. When combined together, all of these issues can have a substantial effect on a rope’s ability to carry loads.

Naturally, it’s not always as drastic as strength loss of 50% or more. Some knots aren’t that damaging, some loads aren’t significant enough to cause stress, and some rope materials, such as polypropylene, Dyneema, and other modern fibers, are more resilient than others. Just keep in mind that any knots or splices will reduce your rope’s operations life span. And that’s before we talk about other factors such as the weather or your rope care regime…

Have you ever wondered how much weight a wire cable can safely hold? It’s surprising how strong wire cables are. Although wire cables often have small diameters and look flimsy, their strength is impressive. Calculating how much weight a wire cable can hold is called a Safe Working Load (SWL), and involves a mathematical formula. The SWL is usually calculated by the manufacturer of the cable and is marked on the packaging to inform consumers. To ensure your safety, always take note of the SWL the manufacturer provides.

SWL can also apply to other lifting devices or components of lifting devices, such as a line, rope or crane. The SWL is also sometimes referred to as Normal Working Load or Working Load Limit. It is the mass that lifting equipment can safely hold without fear of breaking. The SWL or NWL is often a fifth of the Minimum Breaking Strength of the cable, although sometimes other fractions are used, depending on the manufacturer.

To calculate the SWL, you need to know the diameter of the cable or rope. While you may find this on the packaging, you can also calculate it manually by measuring it yourself. Ensure that you enclose all of the strands of rope when measuring the diameter, and measure from the top of one strand to the top of the strand which is directly opposite. If you’re worried about the accuracy of your measurements, conduct your measurements three times at different places on the cable, and use the average of your three measurements as the diameter of the rope.

Once you know the diameter of the rope, you can apply it to the formula, which is SWL = D2 x 8. D represents the diameter of the rope in inches. If you’re working with a 1.5-inch diameter cable, for example, then the formula would be SWL = 1.52 x 8 or SWL = 2.25 x 8. This calculation means the SWL of a 1.5-inch diameter rope is 18 tons.

Take note that most manufacturers will provide you with the SWL for their rope or cable under specific conditions. It’s important to use the SWL the manufacturer gives you. If you’re working with old rope or rope that is worn down, you may want to reduce the SWL of the rope by as much as half, based on the condition of the rope. You can also use the manufacturer’s Breaking Strength of the rope if it is available.

Any job site that utilizes heavy-duty industrial hardware will have a higher rate of job site hazards than the average workplace. Construction zones, transportation services, and manufacturing plants that rely onindustrial chainsfor hoisting, tie-downs, or tension can create dangerous scenarios if they are not mindful of theworking load limit. Miscalculations can cause even strong chains to warp or even break – leading to dangerous and disastrous consequences.

Properly calculating theworking load limitforindustrial chainsis just one of the preventative measures to take to lower these risks. Even though these chains are made from incredibly durable materials, the load-bearing weight should never exceed or even approach the breaking strength. Theworking load limit(WLL) of a chain is a safety precaution to prevent this from happening.

Lower-grade chains (30, 43, and 70) are most commonly used for construction, tie-downs, towing and logging. While these chains are quite durable and have working load limits of up to 15,800 lbs., they are not safe for overhead lifting or rigging applications.

Grade 80 chainsare made from a steel alloy, meaning it contains additional metals for added strength and durability. Grade 80 chains have a breaking load limit of up to 190,800 lbs. and a WLL of 47,700 lbs. They are extremely rugged and often come in a black lacquer finish, which protects the links from damage and wear.

Grade 100 chainsare 25% stronger than Grade 80 and are most commonly used for chain hoists and overhead or even aerial lifts. This style of chain is available in varying lengths and diameters, which can change the breaking load limit and WLL of the entire chain.

The WLL is far lower than the maximum breaking strength of a chain. This is to account for added factors that will create additional tension on the chain apart from the load itself. These factors could include:

The safety factor is a ratio that states how strong of a weight force the chain can withstand before breaking. For most industrial chains, thesafety factor will be 5:1, meaning that if its working load limit is 10,000 lbs. it can technically withstand 50,000 lbs. before snapping. However, this chain should never be used for a 50,000 lbs. load.

Finally, be sure to consider other factors that could lower a chain’s strength, such as its age or condition. The WLL is calculated with brand-new chains, not ones that are worn from previous use. This is why close inspection of chains is always necessary before using them for a new load or application.

Theworking load limitforindustrial chainsis not overly complicated, but you should understand the basic concepts when using this type of hardware. Before placing an order from anindustrial chain supplier, always double-check the WLL along with the accurate load calculation.

The LoosCo Stretch Calculator is the first release in the Loos Mechanicals line of mobile applications designed to assist the wire rope and aircraft cable professional in the field. The Stretch Calculator application provides real time wire rope and aircraft cable elastic stretch estimates based on construction, diameter, length and load inputs provided by the user.

The LoosCo Stretch Calculator application is based on the popular download available on www.loosco.com, and is available for both the iPhone and iPad. The calculator provides the following features:

Loos & Co., Inc. is the world"s leading manufacturer of Military Specification Aircraft Cable and Aircraft Cable assemblies. Loos has over 50 years of experience in the cable industry and supplies flight control assemblies to all major aircraft manufacturers. Refer to our website (www.loosco.com) for a complete listing of capabilities, including: Stainless Steel and Specialty Alloy Wire and Wire Products, Aircraft Cable, Wire Rope, and Military and Commercial Cable Assemblies.

The end fittings at the load will see the same force as the sling connected to it, and they must also be adequate for their intended use. Please consult Northern Strands order desk for capacities with the use of hardware, or the addition of a top Masterlink.

Have you wondered why rigging experts always suggest a sling that has a significantly higher breaking strength than the actual weight of the load you are lifting? The manufacturers know that the rigging used in overhead applications need to have room for error. This is known as the Safety Factor.

Northern Strands manufactures wire rope slings rated up to 36,000 lbs and sells round synthetic slings that are rated up to 140,000 lb capacity. This capacity is the Working Load Limit of the sling, which is the maximum amount of weight or force that the sling"s user is allowed to put on the sling. Note: These slings do not break at the working load limit. These slings are designed with a safety factor of 5:1. This means that 5 times as much force as the working load limit has to be applied to the sling before it potentially fails. This means the wire rope slings have a Breaking Strength of up to 180,000 lbs and the round synthetic slings can withhold up to 700,000 lbs.

Wear - Working load limits are based on slings in brand new condition and a safety factor can help account for normal wear and tear until it is deemed unfit for further use.

Uneven loading - Slings are made up of either wires or fibers that must all share the weight of the load evenly. If any situation arises where the sling is bent or wrapped around an object, there is potential that some of the wires or fibers will be taking on a greater share of the load than others.

Visit Northern Strands website to use the sling tension calculator. The Northern Strands Sling Calculator has been designed to assist you in selecting slings with enough load carrying capacity for your lifting applications. It is your responsibility to assure that the slings you use are appropriate for your application. http://www.northernstrands.com/sling-calculator.aspx