3D Model — Orbit & Inspect
Anatomy of a Chain Sling
Master Link
The top connection point that sits in the crane hook. Must be oblong (not round) so it seats properly in the hook bowl without point-loading.
Intermediate Links
Connect the master link to the sling legs. Allow legs to move freely and distribute load evenly across the master link.
Chain Legs
The working length of the sling. Each link is short-link chain manufactured to AS 2321. Must be Grade 80 or 100 for lifting.
Hooks
Eye hooks (most common), clevis hooks (pin connection), or grab hooks (mid-chain attachment). All must have functioning safety latches.
Shortening Clutch
Adjusts effective leg length to level uneven loads. Must be Grade 80/100 rated. Never tie knots in chain to shorten — reduces capacity by up to 50%.
ID Tag
Permanently attached metal tag showing: WLL, grade, number of legs, chain diameter, serial number, manufacturer, and test certificate number.
Chain Grades
Only Grade 80 (T) and Grade 100 (V) chain is rated for overhead lifting. Grade marking is stamped on every link.
| Grade | Mark | WLL Formula | Max Temp |
|---|---|---|---|
| Grade 80 | T (or 8 / 80) | D² × 32 kg | 200°C |
| Grade 100 | V (or 10 / 100) | D² × 40 kg | 400°C |
Grade 100 is 25% stronger than Grade 80 for the same chain diameter. Both are alloy steel, heat-treated.
Critical Warning
- NEVER use unmarked chain for lifting — if there is no grade stamp on the links, it is NOT rated for overhead use
- Do NOT mix Grade 80 and Grade 100 components in the same sling assembly
- Proof-load / hardware-store chain is NOT lifting chain — regardless of appearance
WLL — Grade 80 (Single Leg Vertical)
Grade 80 WLL Formula
D = chain diameter in mm • Result in kg
| Chain ø | WLL (Single Vertical) | WLL (2-leg 60°) | WLL (2-leg 90°) |
|---|---|---|---|
| 7 mm | 1.5 t | 2.6 t | 2.1 t |
| 8 mm | 2.0 t | 3.5 t | 2.8 t |
| 10 mm | 3.2 t | 5.5 t | 4.5 t |
| 13 mm | 5.3 t | 9.2 t | 7.5 t |
| 16 mm | 8.0 t | 13.9 t | 11.3 t |
| 20 mm | 12.5 t | 21.7 t | 17.7 t |
Load Factors — 2-Leg Sling Assembly
The load factor tells you how much a 2-leg sling assembly can lift as a multiple of one sling leg’s WLL. As the included angle increases, the load factor decreases.
| Included Angle | Load Factor | 2-Leg Capacity | Risk |
|---|---|---|---|
| 0° (parallel) | 2.00 | 2 × single leg WLL | Spreader bar only |
| 60° | 1.73 | 1.73 × single leg WLL | Recommended max |
| 90° | 1.41 | 1.41 × single leg WLL | Caution |
| 120° | 1.00 | 1.00 × single leg WLL | Maximum — Grade 80/100 only |
Never Exceed 120° Included Angle
- At 120° each leg carries a force equal to the full load weight
- Above 120° sling legs are being pulled apart — catastrophic failure risk
- Use a spreader bar or longer slings if the load requires a wider attachment
- Use the 3D model buttons above to visualise 60°, 90°, and 120° configurations
Shortening Clutch
A shortening clutch (also called a chain shortener or grab link) is used to adjust the effective length of a sling leg. This is essential when:
- Levelling an uneven or offset centre-of-gravity load
- Taking up slack in one leg of a multi-leg sling
- Adjusting reach without changing the sling assembly
Correct Use
- Shortening clutch must be Grade 80 or Grade 100 rated — matching the chain grade
- Chain must pass through the clutch freely — no binding or jamming
- Only shorten by the minimum amount needed — excess chain hangs safely below the clutch
- Always verify the shortened sling angle remains within 120°
Never Do This
- Never tie a knot in chain to shorten it — reduces capacity by up to 50% and creates stress concentrations
- Never bolt chain links together as a shortening method
- Never wrap excess chain around the hook or load — creates unpredictable loading
Inspection & Rejection Criteria
Inspect chain slings before every use. Run each leg through gloved hands feeling for rough spots, twisted links, or tight spots.
Reject Immediately If
- Stretched links: any link elongated by >5% of its original length
- Worn links: >10% reduction in material diameter at any point on any link
- Gouges, nicks, or cracks: any surface damage on any link
- Twisted or bent links: links that do not lie flat or articulate freely
- Damaged hooks or latches: bent hook shanks, worn throats (>10%), or non-functioning safety latches
- Missing or illegible tag: no identification = no use
- Mixed grades: Grade 80 and Grade 100 components mixed in the same sling
- Heat damage: discolouration indicating exposure above rated temperature
Good Condition Indicators
- All links articulate freely with no tight spots
- Uniform link dimensions — no visible stretch or wear
- Grade marking (T or V) clearly visible on links
- Hooks swivel freely, safety latches snap closed
- ID tag legible with current test date
- Shortening clutches (if fitted) operate smoothly
Storage & Handling
- Store on racks or hooks — never on the ground where they can be driven over or corroded
- Keep away from chemicals, acids, and salt water — alloy steel corrodes
- Do not drop chain slings — impact can create micro-cracks invisible to the eye
- Never drag chain slings across abrasive surfaces
- Do not shock load — sudden loads can exceed WLL without visible overload
- Tag and quarantine defective slings immediately — do not place back in service
- Chain slings require periodic proof testing per AS 3775 — check test certificates
- Advantage over wire rope: chain does not deteriorate internally — all damage is visible on the surface