A master link assembly is the top of a chain sling supplied ready made and certificated as a unit, rather than built from separate components on site. The DG4 series is a master link with two intermediate links for three and four leg slings.
Buying the assembly made up removes a step that is easy to get wrong: any sling built or altered from loose components requires proof testing and certification by a competent person before it can be used. A certificated assembly arrives ready.
Sizing is by chain diameter, and the published figures give Working Load Limit alongside Manufacturing Proof Force and Minimum Breaking Force — so the margin over the working rating is visible rather than assumed.
Key Features
- DG4 series configuration: A master link with two intermediate links for three and four leg slings
- Supplied made up and certificated: No proof testing step, ready to build into a sling
- 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 +25% of loads: The master link standard at Grade 10 capacity
- -40 °C to +400 °C: Foundry and cold store capable, with derating above +200 °C
- Weights published per size: From 2.46 kg, which matters when the assembly is handled by one person
Technical Specifications
| Product Code |
Part No. |
Chain Dia 3-4 legs (mm) |
W.L.L. (t) |
M.P.F. (kN) |
M.B.F. (kN) |
D (mm) |
L (mm) |
L1 (mm) |
W (mm) |
Weight (kgs) |
| G10DG46 |
D18L13GI |
6 |
3 |
73.6 |
118 |
19 |
135 |
283 |
75 |
2.46 |
| G10DG48 |
D22L16GI |
7/8 |
5.3 |
130 |
208 |
23 |
160 |
347 |
90 |
4.8 |
| G10DG410 |
D26L20GI |
10 |
8.4 |
206 |
330 |
27 |
180 |
413 |
100 |
8.6 |
| G10DG413 |
D32L22GI |
13 |
14 |
343 |
549 |
33 |
200 |
500 |
110 |
16.8 |
| G10DG416 |
D38L26GI |
16 |
21.2 |
520 |
832 |
38 |
275 |
647 |
150 |
29.3 |
Full data for the larger sizes is in the user information sheet.
BS EN 1677-4 +25% of Loads | Grade 10 | 3 And 4 Leg | -40 °C to +400 °C | LOLER Ready
Meets the Working Load Limit performance requirements of BS EN 1677-4 plus 25% of loads. Grade 10 alloy steel with a grey 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 assembly on 3 and 4 leg chain slings across general lifting, machinery handling, fabrication and construction. The wide temperature rating extends its use into foundry, forge and heat treatment work. On three and four leg slings the included angle compounds, so watch it closely.
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
- Check it fits the crane hook: Freely, without being forced or able to tip.
- Watch the included angle: Wide angles raise leg tension sharply. Derate accordingly.
- Assume three legs carry the load: Unless the load is rigid and the legs precisely equal, the fourth leg stabilises rather than lifts.
- 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: On a four leg sling, do not assume the load divides by four. Unless the load is rigid and the legs exactly equal, three legs take the weight. 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 for the number of legs and the included angle.
- 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 link showing wear beyond the manufacturer’s stated limit, elongation, distortion or cracks.
- 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
Inspect every component in the assembly, not just the master link. Measure section diameter at the crown and at each bearing point where links contact one another, and withdraw at the manufacturer’s stated wear limit — the contact faces between links wear against each other and are the points most often missed. Check each link for elongation by measuring internal length, since stretch is direct evidence of overload. Look for nicks, gouges and cracking at the points of maximum curvature, and confirm the links still articulate freely without binding. Confirm the markings and traceability code remain legible.
Downloads
Frequently Asked Questions
Q: Why buy the assembly made up?
Because any sling built or altered from loose components needs proof testing and certification by a competent person before use. A certificated assembly removes that step entirely.
Q: What is the difference between the DG and DCR series?
Both are master link assemblies; the DCR is more compact, shorter overall for the same rating. Compare the L1 dimension. Where headroom is tight, the DCR series buys you some back.
Q: What do M.P.F. and M.B.F. mean?
Manufacturing Proof Force and Minimum Breaking Force. Proof force is what each unit is tested to; breaking force is the design minimum. Both are published per size so the margin over the Working Load Limit is visible.
Q: Can I use it above 200 °C?
Up to +400 °C, with reductions in Working Load Limit. The user information sheet gives the derating. That range is what distinguishes the Kito Grade 10 fittings from most others.
