Lifting Chain & Components

A two-leg sling doesn't lift double a single leg. The working load limit depends on the angle between the legs, and the wider the legs spread, the less the assembly can lift. Every rated sling's tag states its capacity at the marked angle range. If the lift forces a wide angle, the answer is longer legs or a bigger sling, not optimism.

Sling hooks with latches are the default. Self-locking hooks lock under load and open only when slack, worth specifying where a snagged latch is a real risk. Grab hooks and chain shorteners are the right way to take up a leg. Halving a chain around a hook or knotting it damages links and voids the rating.

Single leg, straight vertical lift.

Manufacturer's published figures for grade 80 alloy lifting chain (Beaver). An assembled sling is rated as an assembly: the tag on the sling governs, especially for multi-leg sets and angle ranges.

Two legs don't lift double. The wider the included angle between them, the less the pair can carry.

This is geometry, not a standard being quoted: the factor is twice the cosine of half the included angle. Australian sling tags commonly rate the 60 to 120 degree band. Past 120 degrees a pair carries less than one leg, so the fix is longer legs, not a wider spread.

Strength for size. Grade 100 lifts roughly 25% more than grade 80 at the same chain diameter, so you can run a size smaller and lighter for the same job. Both are proper alloy lifting chain, and the grade is stamped on the links.

As legs spread apart, the tension in each leg climbs above its share of the load. A chain sling's tag gives its capacity for a stated angle range, and outside that range the tag doesn't apply. Keep legs steep. Use longer chains if you can't.

No. Knots and wrapping chain back around a hook load the links sideways and wreck the rating. If a leg needs shortening, the sling should carry a shortener or grab hook rated for the job.

Overhead lifting. It is the standard heat-treated alloy chain for chain slings and lifting assemblies. Transport chain (grade 70, gold coloured) is for lashing loads to trucks. It is not lifting chain, and the two don't swap jobs in either direction.

Chain slings made to AS/NZS 3775 carry a minimum design factor of 4:1 between the working load limit and the chain's breaking force. That margin covers shock, wear and the unexpected. It is the design's insurance, not capacity you can borrow.