Contents
Overview
Lifting eye bolts and other lifting points
Lifting eye bolts screw into a threaded hole in a load to give the sling or hook a rated point to lift from. The marked rating is for a straight pull along the thread. Where the sling legs pull at an angle, use an eye bolt type rated for that angle or a swivel lifting point.
Swivel points and lugs welded or bolted to the load do the same job, and together they are known as lifting points. Work out the sling angle before you choose the eye bolt. Working out the angle is covered in our guide to sling angles.
In short
- A dynamo eye bolt takes a straight pull only. A pair of them needs a lifting beam above the load.
- A collar eye bolt can take an angled pull only in line with the flat of its eye, at a reduced rating.
- A swivel load ring such as RUD’s VLBG is turned to face the pull before the sling goes on, and is not for continuous turning under load.
- Check the eye bolt and the threaded hole before every lift, and withdraw an eye bolt that is bent or cracked.
On a contract lift, our own appointed person plans the lift and writes the lift plan.
Sources
Where the eye bolt guidance comes from
The general rules on this page are mostly drawn from the Lifting Equipment Engineers Association’s Code of Practice for the Safe Use of Lifting Equipment (COPSULE), explained in our LEEA Code of Practice guide, and from the Lifting Operations and Lifting Equipment Regulations 1998 (LOLER), covered in our LOLER guide. Where a point comes from HSE’s guidance or from one maker’s instructions, the page names that source beside it.
Ratings at an angle differ between eye bolt types and standards, and the thread a bolt-on point needs differs between products. Go by the marking and instructions for the eye bolt or lifting point you are fitting, and have the lift planned by a competent person. HSE describes that as someone with enough training and knowledge for the job. On a lift run to BS 7121, the planner is the appointed person, a role set out in BS 7121-1.
Types
Types of lifting eye bolt
COPSULE covers three types of eye bolt for lifting.
Dynamo eye bolts
Plant makers often fit dynamo eye bolts to electric motor casings and similar plant as a low-cost lifting point. The large eye takes a hook of similar capacity directly. A dynamo eye bolt is made for a straight pull along the thread only.
Collar eye bolts
A collar eye bolt has a flat collar under the eye that seats hard against the load. Its eye is smaller, so it needs a shackle between it and the hook. LEEA does not recommend 8 mm and 10 mm collar eye bolts, because they are easily over-tightened and then overloaded.
Eye bolts with link
An eye bolt with link has a link attached to its eye that takes a sling hook directly. For a straight pull it rates lower than a collar eye bolt.
Our lifting accessory standards page covers BS EN ISO 3266, a standard for grade 4 forged steel eye bolts for general lifting.
Angles
What happens when an eye bolt is pulled at an angle
A two-leg sling on a pair of eye bolts pulls each one inwards as well as up, and the wider the legs spread, the further each pull moves off the line of the thread. Use the longest legs possible to keep that angle small, or use a lifting beam or spreader.
An eye bolt’s rating falls once the pull moves away from the line of its thread. LEEA’s limits for each type are:
| Type | Angled pull |
|---|---|
| Dynamo | Straight pull only, so a pair needs a lifting beam. LEEA warns that 5 degrees off line overstresses the thread and shank. |
| Collar | Only within 5 degrees either side of the flat of the eye, so the sling pulls through the eye, not across it. The rating is markedly reduced. |
| With link | Any direction, at the full rating up to 15 degrees from the line of the thread. Beyond that the rating falls, though less steeply than a collar eye bolt’s. |
COPSULE sets out reduction factors for collar eye bolts loaded at an angle, and makers publish figures for their own eye bolts. Use the figure that applies to the eye bolt you are fitting.
Seating and lining up the eye
The collar must sit evenly on a clean, flat face that is square to the thread and big enough for the whole collar. Screw it down until the collar seats firmly, with the flat of the eye lined up with the sling leg. Turning it past tight to line up the eye overloads the shank where the thread meets the collar.
If the eye will not line up, LEEA’s code recommends shims no thicker than half the thread pitch, or machining down the face round the hole so the eye bolt turns further before it seats. Never modify the eye bolt itself.
Slinging
One sling should not be reeved through both eyes as a single loop, because LEEA’s code says this considerably increases the load in each eye bolt. For three or more eye bolts, or where you cannot keep within the limits above, a competent person must be consulted.
Swivel points
Swivel eye bolts and rotating lifting points
Where the sling leg will come in at an angle, or its direction cannot be fixed in advance, use a lifting point that swivels, sold as a swivel eye bolt or load ring.
RUD’s VLBG load ring turns through 360 degrees on its bolt, and its link pivots through 180 degrees, so it can be loaded from any direction. Its instructions say to turn it to face the pull before attaching the sling, and not to use it for continuous turning under load.
Fixed points
Weld-on and bolt-on lifting points
In Great Britain, regulation 4 of LOLER requires every part of a load, and anything attached to it and used to lift it, to be strong enough. Northern Ireland has the same duty in its 1999 regulations.
Plant can have threaded holes that were never meant for lifting, with too little thread or too little metal around them. Have a competent person check any such hole before you lift from it.
Bolt-on lifting points
A bolt-on point needs enough thread in the hole to carry the load. For its VLBG, RUD gives these minimum screw-in depths as multiples of the thread diameter:
| Material | Minimum thread engagement |
|---|---|
| Steel (S235JR or stronger) | 1 × thread diameter |
| Cast iron | 1.25 × thread diameter |
| Aluminium alloys | 2 × thread diameter |
| Aluminium-magnesium alloys | 2.5 × thread diameter |
So an M20 VLBG in steel needs at least 20 mm of thread.
Weld-on lifting points
A weld-on point becomes part of the load, so the weld and the steel under it carry the lift, and regulation 4 applies to both. For its VLBS weld-on load ring, RUD says the welding should be done by an authorised welder to EN ISO 9606-1, the welder qualification standard, or to American Welding Society (AWS) standards, and checked by a competent person before the point is put into use.
Checks
Checks before using an eye bolt or lifting point
Before each use, clean the eye bolt and inspect it in good light. LEEA’s code says the inspection should be done by a suitably qualified and experienced person, and the eye bolt withdrawn if it shows any of these faults:
- Distortion, such as a bent shank or a deformed eye.
- A worn or wrongly formed thread.
- Nicks, cracks, gouges or corrosion, on the thread or anywhere else.
- Missing or unreadable markings, such as the rating and the thread size.
Refer a withdrawn eye bolt to a competent person, such as the engineer who carries out thorough examination of your lifting gear.
Check the hole as well. Its thread must be fully formed and deep enough for the collar to seat, with no debris in it, and it must match the eye bolt’s thread in type and size. LEEA’s code calls mismatched threads extremely dangerous, and says to check carefully wherever there is doubt about a hole’s thread.
For its VLBG load ring, RUD’s instruction handbook says the ring must turn easily before use, and that a competent person should take it out of use once wear exceeds 10 per cent of the cross-sectional diameter.
Eye bolts need thorough examination too, under regulation 9 of LOLER in Great Britain and the matching Northern Ireland regulations. Our guide to LOLER inspections sets out when it is due.
Questions
Common questions
How much weight can an eye bolt hold?
An eye bolt can hold the rating marked on it for a straight pull along the thread. At an angle the safe load falls by an amount set by the type, though an eye bolt with link keeps its full rating up to 15 degrees. The threaded hole and the metal round it must be strong enough too.
What are the three types of eye bolt?
LEEA’s code covers three types of lifting eye bolt. A dynamo eye bolt has a large eye that takes a hook, and is for a straight pull only. A collar eye bolt seats a flat collar on the load and needs a shackle on its smaller eye. An eye bolt with link takes a sling hook on its link.
What is the difference between a shoulder eye bolt and a regular eye bolt?
A shoulder eye bolt has a shoulder under the eye that sits flush on the load, much like the collar in LEEA’s code. A regular eye bolt has none. Crosby’s warnings say never to use its regular nut eye bolts for angled lifts, and LEEA allows a collar eye bolt only a limited angle at a reduced rating.
What angle is not recommended for eye bolts?
For a dynamo eye bolt, any angle: LEEA warns that 5 degrees off the line of the thread overstresses it. A collar eye bolt can take an angled pull only within 5 degrees of the plane of its eye, at a reduced rating. An eye bolt with link keeps its full rating up to 15 degrees from the thread line.
Should lifting eye bolts be tightened?
Yes. Screw a lifting eye bolt down firmly until its collar sits evenly on the load, but do not over-tighten it. If the eye does not line up with the sling, LEEA’s code says not to tighten it further, as that puts too much stress on the shank. The section on seating the eye explains the fixes.
How do you use eye bolts for lifting properly?
Check the eye bolt and its threaded hole first, then screw it down until the collar seats with the eye in line with the sling leg. Use the longest sling legs possible, or a lifting beam to keep each pull straight. Connect a collar eye bolt through a shackle, and never reeve one sling through two eye bolts.
What type of eye bolt should not be used for lifting?
A commercial pattern eye bolt, one not intended for lifting, should never be used to lift. LEEA’s code explains that its thread is rolled or cut with a die head, which tapers the shank where it meets the collar, so the collar cannot seat fully. A lifting eye bolt has a thread runout under its collar instead.
Can you lift a load with one eye bolt?
Yes, if the hook can hang vertically above the load’s centre of gravity, which puts the single eye bolt directly over it. If the load could turn or twist, use a swivel or a swivel hook to stop the eye bolt unscrewing. Our centre of gravity guide explains how to find that point.
What is the British standard for eye bolts?
BS EN ISO 3266 is the UK edition of the European and international standard for forged steel grade 4 eye bolts for general lifting. It covers one-piece eye bolts for straight and angled loading, with the eye sized to take a matching shackle. Our lifting accessory standards page sets it beside the standards for other lifting gear.
When should you use a swivel eye bolt?
Use a swivel eye bolt or lifting point where the sling leg will pull at an angle, or where you cannot tell which way it will pull. A swivel point such as RUD’s VLBG load ring is turned to face the pull before the sling goes on, and can be loaded from any direction once it is lined up.
Get help
Get help with the lifting points on your load
Call us on 0800 008 6096 or email office@synergy-lifting.co.uk. Let us know how much the load weighs and send a photo of each lifting point, with the thread size if you know it, and we will advise on how to rig it.
Machines lifted on and off their bases come under machine delivery and installation. Other crane lifts come under crane hire and contract lifting.
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Send us the details and we will come back with a quote, usually the same day for a desktop survey.
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