The master link is the top of a chain sling — the single component that goes over the crane hook and carries everything below it. Every leg, every fitting and the whole load pass through it.
Sizing is by chain diameter and the number of legs the link will carry, because two legs converging into one link load it differently from one. The other consideration is the crane hook: a master link that will not sit freely in the hook, or one so large it can tip, is the wrong size regardless of its rating.
Working Load Limit, Manufacturing Proof Force and Minimum Breaking Force are published for every size, so the margin over the working rating is visible rather than assumed.
Key Features
- The top of the assembly: Carries every leg and the whole load
- Sized by chain diameter and leg count: Two legs load a link differently from one
- W.L.L., M.P.F. and M.B.F. published: The margin over the working rating is stated, not implied
- BS EN 1677-4: The master link standard
- -40 °C to +400 °C: Against +200 °C for the Cobra Grade 80 range
- Fifteen sizes: With weights published from 0.5 kg
Technical Specifications
| Product Code |
Part No. |
D (mm) |
L (mm) |
W (mm) |
W.L.L. (t) |
M.P.F. (kN) |
M.B.F. (kN) |
Weight (kgs) |
| G8ML87T |
T87-8 |
15 |
120 |
70 |
2.75 |
67.4 |
108 |
0.5 |
| G8ML108T |
T108-8 |
16 |
140 |
80 |
3.55 |
87 |
139 |
0.67 |
| G8ML1310T |
T1310-8 |
20 |
160 |
95 |
5.5 |
135 |
216 |
1.21 |
| G8ML1613T |
T1613-8 |
27 |
190 |
110 |
9.45 |
232 |
371 |
2.65 |
| G8ML2016T |
T2016-8 |
33 |
230 |
130 |
14.2 |
348 |
557 |
4.78 |
| G8ML2220T |
T2220-8 |
38 |
275 |
150 |
22.3 |
547 |
875 |
7.5 |
| G8ML2622T |
T2622-8 |
45 |
340 |
180 |
33.4 |
819 |
1,310 |
12.82 |
| G8ML3226T |
T3226-8 |
50 |
350 |
190 |
40.8 |
1,000 |
1,600 |
16.5 |
| G8ML76W |
W76-8 |
13 |
110 |
60 |
1.6 |
39.2 |
62.8 |
0.53 |
| G8ML87W |
W-87-8 |
16 |
110 |
60 |
2.12 |
52 |
83.2 |
0.53 |
| G8ML108W |
W-108-8 |
19 |
135 |
75 |
3.15 |
77.3 |
124 |
0.92 |
| G8ML1310W |
W-1310-8 |
23 |
160 |
90 |
5.3 |
130 |
208 |
1.6 |
| G8ML1613W |
W-1613-8 |
27 |
180 |
100 |
8 |
196 |
314 |
2.5 |
| G8ML1816W |
W-1816-8 |
33 |
200 |
110 |
11.2 |
275 |
439 |
4.2 |
| G8ML2220W |
W-2220-8 |
40 |
300 |
160 |
17 |
417 |
667 |
8.96 |
Full data for every size is in the user information sheet. Size by chain diameter and leg count together.
BS EN 1677-4 | Grade 8 | -40 °C to +400 °C | LOLER Ready
Conforms to BS EN 1677-4 for master links. Grade 8 alloy steel with a red painted finish. Marked with material grade, manufacturer’s identification, size, product ID mark and traceability code, and supplied with a certificate. Rated -40 °C to +400 °C, with reductions in Working Load Limit above +200 °C. Under LOLER 1998, thorough examination by a competent person at intervals not exceeding 12 months.
Suitable Applications
The top component of single and two leg Grade 8 chain sling assemblies across general lifting, fabrication, machinery handling and construction. For three and four leg slings, a quad master link assembly gives two intermediate links so the legs sit correctly. The wide temperature rating suits foundry, forge and heat treatment work.
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
- Size for the chain AND the leg count: Both matter. Two legs load the link differently from one.
- Check it fits the crane hook: It must sit freely without being forced, and without room to tip.
- Watch the included angle: As the included angle widens, the tension in each leg rises sharply and can approach or exceed the weight of the whole load.
- Keep the assembly one grade: Mixing grades derates the whole sling.
- Derate above +200 °C: Use the figures in the user information sheet.
- Do not modify: Never weld, heat, machine, drill or repaint.
Warning: The master link carries the entire load. A link that does not fit the crane hook freely, or that can tip in the hook, is the wrong size regardless of its rating.
Safety Information
- Never exceed the marked Working Load Limit.
- Use components of the same grade throughout the assembly.
- The master link must fit the crane hook freely without being forced.
- Derate for included angle on multi-leg slings.
- Operating range -40 °C to +400 °C, with derating above +200 °C.
- Withdraw any fitting showing wear beyond the manufacturer’s stated limit, distortion, cracks or elongation.
- Never weld, heat treat, machine or repaint.
- Assemblies built or altered require proof testing and recertification.
- Thorough examination by a competent person required at intervals not exceeding 12 months under LOLER 1998.
Inspection and Maintenance
Measure section diameter at the crown and at every bearing point against original dimensions and withdraw at the manufacturer’s stated wear limit — the crown wears against the crane hook and is usually the worst point. Check for elongation by measuring internal length, since a stretched link is direct evidence of overload and grounds for immediate withdrawal. Look for nicks, gouges and cracking at the points of maximum curvature, and confirm the marking and traceability code remain legible.
Downloads
Frequently Asked Questions
Q: How do I size a master link?
By chain diameter and the number of legs it will carry, not capacity alone. Two legs converging into one link load it differently from one.
Q: Why does the crane hook matter?
A link that will not sit freely cannot align with the load, and one so large it tips is equally wrong. Check the fit before ordering.
Q: What about three and four leg slings?
Use a quad master link assembly — the G8QA range. It puts two intermediate links below the master link so the legs sit correctly.
Q: What do M.P.F. and M.B.F. mean?
Manufacturing Proof Force and Minimum Breaking Force. Proof force is what each link is tested to; breaking force is the design minimum.
