Topic
Lifting gear carries a number that matters more than any other on the part — the working load limit — and most of what goes wrong on a lift comes from reading it wrongly. These guides explain the ratings, the shapes and the inspection criteria, using the figures from our own published tables.
27 articles
A lifting clutch hooks onto the spherical head of an anchor cast into a precast unit, and is released by hand once the unit is set down. The system is only as safe as its weakest decision: the anchor’s load class, the concrete’s strength at lifting, and the angle of pull. Here is how the system works and the rules makers set.
G-209, S-209, G-2130, A-342 — Crosby’s catalogue numbers have become the trade’s shorthand for rigging shapes. The letter tells you the finish or material; the number tells you the shape. Here is the key, a table of the common numbers, and why a part made to a Crosby pattern is not a Crosby part.
New lifting gear arrives with a manufacturer’s certificate; gear in service carries a report of thorough examination. They answer different questions. The first proves the item was made and tested to its standard; the second says it was fit to use on the day it was examined. Here is what each must contain, and the checks to make before the first lift.
A sling with ten broken wires in one lay, a chain link worn by a tenth, a hook opened by 15%, a polyester sling with a cut deeper than a tenth of its width, or any item with no readable tag — each comes out of service. Here are the discard criteria for every common piece of lifting gear, in one place.
DIN link chains are named for their link length and whether they are tested and calibrated — and the current DIN 764 and DIN 766 are written for chain conveyors, with an explicit ban on use as slings or lifting accessories. Here is what each standard covers, how they compare with Grade 80 lifting chain, and what they are actually for.
A lever binder tensions a chain in one swing of the handle — and can whip back just as fast. A ratchet binder takes longer to tighten but gives twice the mechanical advantage and a controlled release. Both carry the same rating for the same chain size. Here is how they compare and how to use either safely.
A 50 mm ratchet strap might be rated 2,000 daN, yet tightened by hand it typically pulls only 250 to 500 daN on the load. That gap decides how loads are secured: straps are good for clamping light and finished loads down; chain and binders for heavy, hard-edged ones. Here is how the ratings work and how many tie-downs a load needs.
On the Gulf coast, zinc on galvanized rigging can be lost at up to 8 µm a year, and faster offshore. Stainless steel does not rust away, but it pits in salt air, can crack in hot chloride conditions, and is usually rated well below carbon or alloy steel of the same size. Here is how to choose.
A properly poured spelter socket keeps 100% of the wire rope’s breaking load — the only end fitting besides a swaged socket that does. Open sockets connect with a pin through their jaws; closed sockets take a pin or shackle through a solid eye. A wedge socket is quicker to fit but keeps 80%. Here is how to choose and what a good socket needs.
Every way of making an eye in wire rope keeps a different share of the rope’s strength. Sockets keep all of it; ferrule-secured and Flemish eyes about 90% or better; a hand splice less, and less again as the rope gets bigger. Here is the efficiency table, how each eye is made, and where each one belongs.
A thimble keeps a wire rope eye from crushing and wearing where it bears on a shackle or pin. It is not rated to carry load itself — it protects the rope that does. Here is how standard, extra-heavy and solid thimbles differ, and how to match one to the rope and the fitting.
A weld-on lifting point is only as good as its weld. A bolt-on point is only as good as its thread engagement and torque. A swivel point turns to face the sling, but not every one keeps its full rating sideways. Here is how the four kinds of lifting point compare, and what each needs to be fitted properly.
Hooks are chosen on two things: how they attach (eye, clevis, shank or swivel) and what they do (a sling or slip hook holds a load in its bowl; a grab hook grips a chain link). Use a grab hook to shorten a chain and the sling loses 20% unless the hook is a cradle type. Here is how the types differ, and when a hook comes out of service.
The master link is the top of a multi-leg sling: it gathers the legs and sits in the crane hook. Two legs can share a single master link; three or four need an assembly with sub-links. And the link has to fit the hook as well as the chain. Here is how to choose one.
A chain block lifts straight up and down, from overhead. A lever hoist pulls, lifts and tensions in any direction, as long as the pull runs straight hook to hook. An electric hoist does the work for you, all day, rated by duty class. Here is how they compare and which one fits the job.
A snatch block opens at the side so a rope can be dropped in without threading the end through. That is its whole difference from a pulley block — but either one can carry nearly twice the line pull, depending on the angle. Here is how to work out the block load, size the sheave and count the parts of line.
Chain slings survive heat, edges and rough handling. Wire rope slings are strong and stiff. Webbing and round slings are light and gentle on finished surfaces, but cut easily and stop at 100 °C. Here is how the four compare, and how to choose for the load in front of you.
Under EN 1492, a violet polyester sling is rated 1 t, green 2 t, yellow 3 t, grey 4 t, red 5 t, brown 6 t, blue 8 t and orange 10 t or more. US round slings follow a different scale, so a green sling can mean 2 t or 5,300 lb depending on where it was made. Here is the chart — and why the label, not the colour, is the rating.
A turnbuckle is only as strong as its weakest end, and that is usually the hook: on our US drop-forged range a 1/2″ hook end is rated 1,500 lb against 2,200 lb for eye or jaw ends. Here is how end fittings and body types change the rating, which standards cover what, and how to keep a turnbuckle from unwinding.
A plain eye bolt is rated for a straight pull only. A shoulder eye bolt pulled at 45° keeps 30% of its rating. A DIN 580 collar eye bolt has its own table for angled loads and none at all for a pull across the eye. Here is how each type is rated, fitted and derated.
In Abu Dhabi, lifting accessories must be thoroughly examined by an approved third party at least every six months and lifting equipment every twelve — it is written into the emirate’s code of practice. Dubai requires annual certification by an EIAC-accredited inspector, and accredited inspectors apply six months to accessories. Here is what each document says.
A wire rope clip termination is only as good as its installation: the saddle on the live end, the right number of clips, the right length of turnback and the right torque, re-checked after the first load. Here are the published tables for US-type and DIN 1142 clips, and the one job clips must never do.
Two sling legs do not each carry half the load unless they hang straight down. At 45° from vertical each leg carries 71% of the load; at 60° each carries all of it. Here is the chart, the one-line formula behind it, and how rating tables for multi-leg slings build it in.
A wire rope designation such as 6x36WS-IWRC 1770 B sZ tells you almost everything about how the rope will behave. The surprise is how little the construction changes its strength: at 12 mm, the common six-strand ropes break within about 12% of each other. What changes is flexibility, abrasion resistance and crush resistance.
Chain grade is a statement about the steel, and it decides two things: how much a given size carries, and whether it may be used overhead at all. Grades 30, 43 and 70 are for tie-down and towing. Only alloy Grade 80 and Grade 100 are lifting chain. Here is the whole ladder, with figures from our own tables.
A shackle is chosen on two decisions: the body shape, which sets the directions it can be loaded from, and the pin, which sets how securely it stays closed. Here is how anchor and chain shackles differ, when each pin type is right, and how material changes the rating at the same size.
The breaking strength of a lifting component is not a number you lift to. It is the WLL multiplied by a design factor, and that factor runs from 4:1 on alloy chain to 7:1 on polyester slings. Here is how the four ratings relate, worked through with figures from our own tables.
