Four chain legs will not fit properly into a single master link. They crowd, sit unevenly and load the link across its width rather than along its length. The quad assembly solves that: a main link that takes the crane hook, with two sub-links hanging beneath it, each carrying two legs. The load spreads correctly, each leg sits square, and the geometry stays predictable under load. Supplied assembled and certificated. Grade 10 alloy steel to BS EN 1677-4, W.L.L. 3 tonnes to 85 tonnes.
Key Features
- Correct geometry for three and four legs: Two sub-links spread the legs so each sits square and loads evenly, which a single link cannot do with four legs.
- Supplied assembled: Arrives built and certificated as an assembly, ready for the chain legs to be fitted.
- W.L.L. 3 t to 85 t: Nine sizes with published proof load and breaking load throughout.
- 4:1 safety factor: Minimum breaking load is four times the Working Load Limit. The 21.2 tonne assembly breaks at 84.8 tonnes.
- Sized by chain diameter: Each assembly is specified against the chain size of the legs it carries, from 6 mm through 32 mm.
- Substantial main link: Internal width from 75 mm to 250 mm, accepting large crane hooks on the heavier assemblies.
- Full traceability marking: Material grade, manufacturer's identification, size, product ID mark and traceability code.
Technical Specifications
| Product Code |
Chain (mm) |
W.L.L. (t) |
M.P.L. (t) |
M.B.L. (t) |
d (mm) |
D1 (mm) |
W (mm) |
W1 (mm) |
L (mm) |
L1 (mm) |
Weight (kg) |
| G100QA6 |
6 |
3 |
6 |
12 |
18 |
14 |
75 |
25 |
135 |
54 |
1.26 |
| G100QA8 |
8 |
5.3 |
10.6 |
21.2 |
22 |
16 |
90 |
34 |
160 |
70 |
2.19 |
| G100QA10 |
10 |
8.4 |
16.6 |
32 |
27 |
18 |
100 |
40 |
180 |
85 |
3.6 |
| G100QA13 |
13 |
14 |
28 |
56 |
33 |
22 |
110 |
50 |
200 |
115 |
6.35 |
| G100QA16 |
16 |
21.2 |
42.4 |
84.8 |
36 |
28 |
140 |
65 |
260 |
140 |
10.61 |
| G100QA20 |
20 |
33.6 |
67.2 |
134.4 |
50 |
32 |
190 |
90 |
350 |
180 |
23.67 |
| G100QA22 |
22 |
39.9 |
79.8 |
159.6 |
50 |
36 |
190 |
100 |
350 |
180 |
26 |
| G100QA26 |
26 |
56 |
112 |
224 |
60 |
45 |
200 |
100 |
400 |
180 |
42.6 |
| G100QA32 |
32 |
85 |
170 |
340 |
72 |
50 |
250 |
110 |
460 |
200 |
66.7 |
All dimensions in millimetres, weights in kilograms. d is the main link section, D1 the sub-link section, W and W1 the internal widths. The 26 mm and 32 mm sizes are available to order.
BS EN 1677-4 | Grade 10 | 4:1 Safety Factor | Supplied Assembled | LOLER Ready
Grade 10 alloy steel, quenched and tempered, meeting the Working Load Limit performance requirements of BS EN 1677-4 plus 25% of loads. Minimum breaking load is four times the marked W.L.L. Supplied assembled and certificated. Each component is marked with material grade, manufacturer's identification, size, product ID mark and traceability code. Under LOLER 1998, lifting accessories require thorough examination by a competent person at intervals not exceeding 12 months.
Suitable Applications
Quad master link assemblies are the standard top termination for three and four leg chain slings, which are used wherever a load needs support at multiple points to stay level and stable. That covers plant and machinery lifting using four lifting eyes, fabricated steelwork, precast concrete units, tanks and vessels, and any load whose centre of gravity is off centre. They are also used as intermediate collectors on complex assemblies. For single and two leg slings a plain master link is lighter, simpler and cheaper.
More About This Product
Shackles are the most-handled component in any lifting operation, and that is precisely why they wear out first. A sling gets rigged and derigged; a shackle gets rigged, derigged, dropped, driven over, thrown into a box and picked up by whoever needs one. Most lifting gear fails from a single overload; shackles fail from accumulated inattention.
The grade markings matter more than most people realise. A Grade 6 high tensile shackle to BS EN 13889 and a Grade 8 alloy shackle look similar and share the same body shape, but the alloy version carries considerably more at the same size. Once a shackle is in a box with fifty others, the only way to tell them apart is the marking — which is why an unmarked shackle has to be scrapped no matter how good it looks.
Understanding the Load Path
A shackle has two distinct load-bearing elements and they do different jobs. The bow takes the sling; the pin takes the load. Reverse that — put the sling on the pin and the load on the bow — and two things happen. The sling bears on a smaller radius than it was designed for, and any movement in the sling starts to rotate the pin.
On a screw collar pin that rotation is the failure mechanism. A sling shifting under a settling load, or vibration transmitted from plant nearby, will slowly unscrew the pin over minutes or hours. It rarely happens quickly enough for anyone to see it happening.
The second consideration is angle. A shackle loaded in line with the pin carries its full rating. Loaded at an angle across the bow it carries substantially less, and published derating tables cover a limited range of angles — beyond that range no figure is published because none applies. On a multi-leg sling every leg is at an angle by definition, which is why the bow shackle exists and why putting a multi-leg sling into a dee shackle is a genuine mistake rather than a preference.
How to Use the Quad Master Link Assembly
- Size against the chain: Select by the chain diameter of the legs. A G100QA13 is for 13 mm Grade 10 chain.
- Two legs per sub-link: Fit two legs to each sub-link on a four leg sling. On a three leg sling, two on one sub-link and one on the other.
- Check the crane hook seats in the main link: The main link must sit in the hook throat, not on the tip.
- Understand four leg load sharing: On a rigid load, only three legs may actually carry load at any moment. Rate the sling as though it were three leg unless the load is genuinely flexible.
- Derate for sling angle: Wider included angles increase leg loads substantially. A 90 degree included angle on a four leg sling is a common working case and must be calculated.
- Do not modify: Never weld, heat, machine, drill or repaint.
Warning: On a rigid load lifted by four legs, only three may carry the load at any one time. Calculate accordingly rather than assuming the mass divides by four. Never exceed the marked Working Load Limit, and derate for included angle.
Safety Information
- Never exceed the Working Load Limit for the size.
- Maximum two chain legs per sub-link.
- On rigid loads, assume three of four legs carry the load.
- Derate for included angle on all multi-leg slings.
- Use only with Grade 10 chain and components of the matching size.
- Withdraw from service any assembly showing elongation, distortion, cracks or wear beyond the manufacturer’s stated limit of original section.
- Never weld, heat treat, machine or repaint.
- Do not use above +200 °C or below -20 °C.
- Thorough examination by a competent person required at intervals not exceeding 12 months under LOLER 1998.
Inspection and Maintenance
A quad assembly has more wear points than a plain link and each needs checking. The main link wears at the crown where the hook bears and at the bottom where the sub-links sit. The sub-links wear at both ends, against the main link above and the chain legs below. Measure section diameters d and D1 at each of those points and withdraw at 10% loss. Check overall lengths L and L1 for elongation against the table, and look for the sub-links having pulled out of plane, which indicates uneven leg loading. Because the assembly is supplied built, also confirm the sub-links still move freely on the main link rather than having worn into a groove.
Frequently Asked Questions
Q: Why can I not just use a bigger master link for four legs?
Because the legs would crowd against each other and load the link across its width rather than along its length, which is the direction it is weakest in. The two sub-links give each pair of legs its own bearing point and keep the loading along the correct axis.
Q: Does a four leg sling lift four times a single leg?
No, and this catches people out. On a rigid load, manufacturing tolerances mean only three legs are likely to be carrying load at any moment. Standard practice is to rate a four leg sling on a rigid load as though it were three leg. Only on a genuinely flexible load can all four be assumed to share.
Q: Three leg or four leg?
Three legs always share the load predictably, since three points define a plane. Four legs give better stability on a large or long load but share less predictably. The quad assembly handles either; the difference is in how you rate the sling.
Q: Does it come assembled?
Yes, supplied built and certificated as an assembly. You fit the chain legs to the sub-links, and the completed sling then needs proof testing and certification by a competent person before use.
