Eye Bolts & Lifting Points Singapore | Types, SWL & MOM Compliance Guide | FRT
- Jul 20
- 9 min read
Eye bolts and lifting points are among the most widely used — and most dangerously misused — pieces of rigging hardware on Singapore worksites. They are fitted to machinery, equipment, structural steel, and fabrications to provide a lifting attachment point. Used correctly, they are safe and reliable. Used incorrectly, they fail suddenly and without warning.
The most common mistake — and it happens daily on Singapore construction sites, in workshops, and in shipyards — is applying an angled load to an eye bolt that is only rated for vertical loading. The result is a catastrophic reduction in SWL that most operators are completely unaware of.
This guide covers everything you need to know — the different types of eye bolts and lifting points, their SWL ratings, how angle loading affects capacity, installation requirements, inspection criteria, and MOM compliance obligations in Singapore.
Types of Eye Bolts and Lifting Points
1. Plain (Collar-Less) Eye Bolt
The simplest eye bolt — a threaded shank with a circular eye at the top and no shoulder or collar.
Key characteristics:
No shoulder or collar to seat against the load surface
Rated for vertical loading only — any side or angled load drastically reduces capacity
Lowest cost eye bolt type
Not recommended for general lifting use where any angle loading is possible
SWL reduction with angle loading (plain eye bolt):
Angle from Vertical | SWL as % of Rated Vertical SWL |
0° (vertical) | 100% |
15° | 65% |
30° | 35% |
45° | 25% |
>45° | Do not use |
This table is the most important thing to understand about plain eye bolts. At just 30° from vertical, a plain eye bolt retains only 35% of its rated SWL. At 45°, only 25%. Most rigging setups on Singapore worksites involve some degree of angle — which is why plain eye bolts are inappropriate for the majority of lifting applications.
When plain eye bolts are acceptable:
Vertical single-leg lifts only
Where the rigging setup can guarantee the load will always hang perfectly vertical
Low-load, low-risk applications with engineering confirmation
2. Shoulder (Collar) Eye Bolt
A shoulder eye bolt has a machined collar or shoulder at the base of the eye that seats flush against the load surface when correctly installed. The shoulder dramatically improves resistance to angled loading compared to a plain eye bolt.
Key characteristics:
Collar seats against the load surface — provides lateral support for angled loads
Rated for angled loading — but SWL still reduces with increasing angle
Must be correctly installed with the collar fully seated and the eye oriented in the plane of the lift
The most widely used eye bolt type for general lifting in Singapore
SWL reduction with angle loading (shoulder eye bolt):
Angle from Vertical | SWL as % of Rated Vertical SWL |
0° (vertical) | 100% |
15° | 75% |
30° | 55% |
45° | 35% |
60° | 25% |
>60° | Do not use |
Even with a shoulder eye bolt, a 45° load angle reduces SWL to just 35% of the rated vertical capacity. For multi-leg lifts where sling legs pull at significant angles, the shoulder eye bolt SWL must be de-rated accordingly — and the eye bolt must be oriented so the eye is in the plane of the sling pull.
Critical installation requirement: The eye of the shoulder eye bolt must be oriented in the plane of the applied load — the sling must pull through the eye in the direction the eye faces, not across it. Loading a shoulder eye bolt across the plane of the eye (in the wrong direction) creates bending loads the eye bolt is not designed for.
3. Swivel Hoist Ring (Swivel Eye Bolt)
A swivel hoist ring — also called a swivel eye bolt or swivel lifting point — has a rotating bail (the ring that connects to the sling) mounted on a swivel mechanism that allows the bail to rotate 360° around its axis and pivot up to 180° in the plane of loading.
Key characteristics:
The bail rotates and pivots freely to align with the applied load direction
Rated for full SWL at any angle — no de-rating for angled loading
Eliminates the need to orient the lifting point before the lift
Significantly reduces the risk of cross-plane loading errors
Higher cost than fixed eye bolts — but the safety and operational advantages justify it for critical and frequent lifts
The preferred choice for multi-leg lifts, angled lifts, and any application where the load direction may be uncertain
When swivel hoist rings should be specified:
Multi-leg sling lifts where each leg pulls at a different angle
Any lift where the exact load direction cannot be predicted or controlled
Offshore and marine lifts where load direction may shift during the lift
Precision machinery lifts where alignment of fixed eye bolts adds time and risk
High-value equipment where the consequences of eye bolt failure are unacceptable
Any frequent lifting application where operational efficiency matters
4. Weld-On Lifting Lugs
A lifting lug is a steel plate with a hole or shackle slot that is welded directly onto the load — a fabricated steel structure, vessel, tank, or frame. The lug becomes a permanent part of the load.
Key characteristics:
Welded directly to the structure — no threaded connection
Designed by a structural engineer for the specific load and lift geometry
Load rating depends entirely on the lug design, weld size, and parent material
Must be proof load tested after fabrication and welding
Common on Singapore fabrications, pressure vessels, offshore structures, and structural steelwork
Critical requirements:
Weld quality is everything — a poor weld on a lifting lug is a hidden failure waiting to happen
The lug design must be verified by a qualified structural or mechanical engineer
Parent material must be of a grade suitable for welding under the applicable standard
All lifting lugs must be proof load tested before first use — FRT's load testing services cover lug testing
5. Recessed (Flush) Lifting Points
Recessed lifting points are threaded inserts that sit flush with or slightly below the surface of machinery or equipment. They accept a matching lifting bolt that screws in for lifting and is removed when not needed — leaving a flush, unobtrusive surface.
Key characteristics:
Clean appearance when not in use — no protruding eye bolt
Common on precision machinery, machine tools, and equipment where protruding hardware would be a hazard
The threaded insert and mating bolt are a matched system — never substitute a non-matching bolt
SWL is typically stamped on the insert or specified in the equipment manual
The Most Critical Rule: Angle Loading Kills Eye Bolt Capacity
This cannot be overstated. The single most dangerous mistake with eye bolts in Singapore is using a plain or shoulder eye bolt in a multi-leg sling configuration without applying the angle de-rating factor.
Worked Example — Why This Matters
Scenario: You need to lift a 4-tonne machine using a two-leg sling. Each leg of the sling connects to a shoulder eye bolt on the machine. The angle between the two sling legs is 90°, which means each leg pulls at 45° from vertical.
What most people assume:
Eye bolt rated SWL: 2T each
Two eye bolts: 2T + 2T = 4T total capacity ✅ — seems fine for a 4T lift
What is actually happening:
At 45° from vertical, each shoulder eye bolt retains only 35% of its rated SWL
Actual SWL per eye bolt at 45°: 2T × 0.35 = 0.7T
Total actual capacity: 0.7T + 0.7T = 1.4T
Load weight: 4T
Result: The eye bolts are being loaded at nearly 3× their actual capacity at the rigging angle being used. This is a catastrophic overload — and it looks completely normal on the surface because the eye bolts are rated at 2T each.
The solution: Either use swivel hoist rings (no angle de-rating), use a spreader beam to keep the sling legs vertical, or specify larger shoulder eye bolts that retain sufficient SWL at the actual rigging angle.
For the full SWL angle factor calculation method, refer to our [SWL calculation guide →]
Eye Bolt Installation: What Must Be Done Correctly
Incorrect installation is responsible for a large proportion of eye bolt failures. Follow these requirements without exception:
Threaded Eye Bolts
Thread engagement: The eye bolt must be screwed in to its full thread depth — the shoulder must seat fully and flush against the load surface. A partially threaded eye bolt has dramatically reduced capacity. Never use packing washers or spacers under the shoulder to achieve alignment — this defeats the shoulder's purpose entirely.
Thread condition: The threads in the tapped hole must be clean, undamaged, and of the correct size and pitch for the eye bolt. Damaged threads must be re-tapped or the hole replaced before the eye bolt is used.
Material compatibility: The eye bolt grade must match the tapped hole material. A high-grade eye bolt installed in a low-strength casting or aluminium housing may strip the threads under load. Confirm thread engagement strength with an engineer where there is any doubt.
Orientation: For fixed shoulder eye bolts, the eye must be oriented in the plane of the sling pull before the lift begins. This means the eye faces in the same direction as the sling will pull. Rotating the eye bolt to achieve this orientation may require a shim under the shoulder — use a purpose-made shim, not a random washer.
Weld-On Lifting Lugs
Weld procedure: Welding must be carried out by a qualified welder to an approved welding procedure. The weld size and type must match the engineering design. Fillet welds on lifting lugs are the most common — verify the leg length and profile match the design drawing.
Post-weld inspection: All lifting lug welds must be inspected after welding — visually as a minimum, with magnetic particle inspection (MPI) or dye penetrant inspection (DPI) for critical applications. Never load a lifting lug without weld inspection.
Proof load testing: All lifting lugs must be proof load tested to 2× SWL before first use. FRT's load testing services cover lifting lug proof load testing with full documentation.
Eye Bolt Inspection: What to Check
Before Every Use
Thread condition — eye bolt must be fully seated with shoulder flush against surface
Eye condition — no cracks, deformation, or wear at the sling contact point
SWL marking — legible SWL and grade marking on the eye bolt body
Overall condition — no corrosion, deformation, or damage to the shank or eye
When to Retire Immediately
Any crack — in the eye, at the shoulder, or on the shank
Deformation of the eye — any distortion from the original circular shape
Corrosion — pitting corrosion on the shank or eye contact surface
Thread damage — stripped, cross-threaded, or corroded threads
Elongation of the eye — the eye has been pulled into an oval shape
Unknown history — any eye bolt without a traceable test certificate
Formal Inspection — Every 12 Months
All eye bolts and lifting points in service must be formally inspected by a MOM-recognised AE or Competent Person at intervals not exceeding 12 months. Inspection records must be maintained.
MOM Compliance Requirements for Eye Bolts in Singapore
Under Singapore's WSH (Lifting Operations) Regulations:
Before first use:
Proof load tested to 2× SWL
Test certificate issued
SWL permanently marked on the body
In service:
Pre-use inspection before every lift
Formal inspection by Competent Person at least every 12 months
Inspection records maintained
Colour coding to match current inspection year
Design and installation accountability: Where eye bolts or lifting lugs are being specified as part of a lifting plan for a significant lift, the design must be reviewed by a Competent Person who confirms the SWL — including the angle de-rating — is adequate for the planned lift.
Choosing the Right Lifting Point: Quick Decision Guide
Situation | Recommended Lifting Point |
Vertical single-leg lift, controlled conditions | Shoulder eye bolt |
Multi-leg lift with angled sling legs | Swivel hoist ring |
Lift where load direction is uncertain | Swivel hoist ring |
Permanent attachment to fabricated structure | Weld-on lifting lug |
Precision machinery with flush surface requirement | Recessed lifting point |
Offshore or marine critical lift | Swivel hoist ring |
Budget-driven, vertical lift only, low risk | Plain eye bolt (with care) |
High frequency lifting of same load | Swivel hoist ring |
The safest default for any multi-leg or angled lift: always specify a swivel hoist ring. The additional cost is negligible compared to the risk of eye bolt failure from angle loading.
Eye Bolts and Lifting Points Available From FRT in Singapore
FRT supplies a complete range of eye bolts and lifting points for Singapore's construction, marine, industrial, and machinery sectors:
Plain eye bolts — DIN 580, Grade 4.6 and 8.8, galvanised and stainless steel
Shoulder eye bolts — DIN 582 and BS 4278, Grade S, galvanised and stainless steel
Swivel hoist rings — full 360° rotation and 180° pivot, Grade S, for angled and multi-leg lifts
Stainless steel eye bolts — Grade 316, for marine and corrosive environments
Custom lifting lugs — design and fabrication service available, proof load tested
All products supplied with test certificates meeting MOM requirements. Custom fabrication and proof load testing services available for lifting lugs and special lifting points.
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