Our eyebolts and carriage bolts serve lifting, anchoring, and timber-fixing tasks. Forged lifting eyebolts (DIN 580) provide a rated attachment point for slings and rigging, while cup square carriage (coach) bolts (DIN 603) pull into timber for a flush, tamper-resistant fixing. Both are stocked in steel and stainless steel.

Eyebolts & Carriage Bolts - Metric Sizes

What Are Eyebolts and Carriage Bolts?

Eyebolts and carriage bolts are two distinct Metric Specialties fasteners grouped by their non-standard heads. An eyebolt is a bolt with a looped or ring head that provides a secure attachment point for ropes, cables, chains, and lifting slings. Forged lifting eyebolts manufactured to DIN 580 are heat-treated and rated for overhead lifting, giving riggers a certified anchor point on machinery, moulds, and heavy assemblies. Non-lifting eyebolts serve tie-down, guy-wire, and light anchoring duties.

A carriage bolt  also called a coach bolt or cup square bolt  has a smooth, domed head above a square shoulder. When driven into timber or a square hole, the shoulder embeds and prevents the bolt from spinning, so it can be tightened from the nut side with a single wrench. The domed head leaves a clean, rounded finish with no exposed drive, giving a tamper-resistant, snag-free surface widely used in timber construction, decking, gates, and machinery guards. Both types are stocked in zinc-plated steel and A2/A4 stainless.

Key Features and Benefits

• Rated Lifting Points: Forged DIN 580 eyebolts provide certified, load-rated anchor points for slings and rigging.
• Anti-Rotation Fixing: The carriage bolt's square shoulder embeds in timber, letting it be tightened from the nut alone.
• Clean Domed Head: Carriage bolts leave a smooth, tamper-resistant finish with no exposed drive recess.
• Versatile Anchoring: Eyebolts secure ropes, cables, and chains for lifting, tie-down, and guying.
• Corrosion Options: Zinc-plated and A2/A4 stainless grades suit indoor to marine and outdoor use.

Materials and Finishes

• Forged Alloy Steel (Eyebolts): Heat-treated, load-rated material for certified overhead lifting.
• Carbon Steel (Zinc Plated): General-purpose carriage bolts for timber and construction.
• Hot-Dip Galvanised: Heavy outdoor corrosion protection for structural timber fixings.
• Stainless Steel A2 / A4: Corrosion-resistant eyebolts and carriage bolts for marine and outdoor use.

Standards Compliance

• DIN 580  Forged lifting eyebolts.
• DIN 582  Lifting eye nuts.
• DIN 603  Cup square (carriage) bolts.

Common Applications and Industries

Lifting eyebolts are essential in manufacturing, engineering, and logistics, providing rated attachment points to lift machinery, dies, moulds, motors, and heavy assemblies with slings and rigging. Non-lifting eyebolts anchor cables, guy wires, and tie-downs in fencing, marquees, and light rigging. Because certified lifting depends on them, forged DIN 580 eyebolts are specified wherever loads are raised overhead.

Carriage bolts are a mainstay of timber construction, decking, fencing, gates, and playground equipment, where the domed head gives a smooth, tamper-resistant finish and the square shoulder locks the bolt in the wood. They also secure machinery guards and brackets where a clean head and single-wrench installation are valued. Galvanised and stainless versions serve exposed outdoor and coastal structures.

How to Choose the Right Eyebolt or Carriage Bolt

For lifting, always select a forged, load-rated eyebolt such as DIN 580, sized and oriented for the load and sling angle, and never substitute a bent-wire eyebolt. For anchoring and tie-down only, a non-rated eyebolt may suffice. Confirm the thread and length engage fully into the tapped hole or nut.

For carriage bolts, ensure the square shoulder suits the timber or square hole so the bolt locks against rotation, and choose a length that passes through the assembly with room for a washer and nut. Select the finish for exposure  zinc-plated for light outdoor use, hot-dip galvanised for heavy outdoor duty, and A2 or A4 stainless for coastal and marine environments.

Size Range and Availability

Eyebolts available M6 through M48 rated for lifting; carriage bolts available M6 through M20, in zinc-plated, galvanised, and A2/A4 stainless finishes.

Why Buy From Metric Specialties

As dedicated metric fastener specialists, we hold eyebolts & carriage bolts in the sizes, grades, and finishes that engineers actually need, backed by clear DIN and ISO standard references so you can specify with confidence. Every item is sourced to recognised standards and quality-controlled, giving you consistent thread fit, strength, and corrosion performance across repeat orders.

Whether you need a single item for a repair or bulk quantities for production, our range, technical guidance, and fast dispatch help you find the exact fastener for the job. If you are unsure which size, grade, or finish suits your application, our team can help you match the right product to your load, environment, and standard, so your assemblies are reliable and built to last.

Frequently Asked Questions (FAQs)

1. What is a lifting eyebolt used for?

A forged lifting eyebolt (DIN 580) provides a rated attachment point for slings, chains, and rigging to lift machinery, moulds, and heavy assemblies safely. Only load-rated eyebolts should be used for overhead lifting.

2. What is a carriage bolt used for?

A carriage (coach) bolt is used to fix timber and to create a smooth, tamper-resistant fixing. Its square shoulder embeds in the material so it can be tightened from the nut side with a single wrench.

3. Why does a carriage bolt have a square section under the head?

The square shoulder embeds into timber or fits a square hole, preventing the bolt from spinning as the nut is tightened. This lets the bolt be installed and tightened with access to the nut only.

4. Can I use any eyebolt for lifting?

Not only forged, load-rated lifting eyebolts such as DIN 580 should be used for overhead lifting. Bent-wire and non-rated eyebolts are for light tie-down and anchoring, never for suspending loads.

5. What is the difference between an eyebolt and an eye nut?

An eyebolt has a threaded shank with a looped head, while an eye nut (DIN 582) has an internal thread and looped body that screws onto a threaded rod or stud. Both create a lifting or anchor point.

6. Are carriage bolts available in stainless steel?

Yes. We stock A2 and A4 stainless carriage bolts for corrosion-resistant timber and construction fixings in outdoor, coastal, and marine environments.

7. How should lifting eyebolts be installed?

Lifting eyebolts must be fully seated against the load surface with the eye correctly oriented to the sling direction, and used within their rated capacity and angle limits. Follow the applicable lifting regulations.

8. What finishes protect eyebolts and carriage bolts outdoors?

Zinc plating suits light outdoor use, hot-dip galvanising provides heavy outdoor protection, and A2/A4 stainless resists corrosion in coastal and marine conditions.

9. What sizes do you stock for eyebolts and carriage bolts?

We stock lifting eyebolts M6 through M48 and carriage bolts M6 through M20, in zinc-plated, galvanised, and A2/A4 stainless finishes.

10. Do carriage bolts need a washer?

A washer is normally used under the nut to spread load and protect the surface. The domed head side needs no washer because the smooth head bears directly and the square shoulder locks it in place.