What is the difference between eyebolts

Lifting eyebolts and swing bolts share a ring-shaped head and in English both are called eyebolts, but they are two different fasteners with different standards, load cases and safety rules. Treating them as interchangeable can end in a failed installation or a lifting accident, so project buyers should state the full standard number instead of writing only eyebolt, and keep lifting hardware apart from sealing items such as flange gaskets.

Lifting Eyebolt and Swing Bolt: Core Differences

A catalogue photo makes the two parts look identical, yet their standards, functions and manufacturing routes differ. The comparison below covers the points that matter at purchase and at site.

Note: standards and property classes follow the marking on the product; sizes refer to nominal thread size.

The functional split is simple: a lifting eyebolt takes axial tension during hoisting and is treated as a lifting component, while a swing bolt gives a pivotable, detachable fastening and is handled as a standard fastener.

Lifting Eyebolt (DIN 580): Standard, Shape and Safe Use

The mainstream international standard for lifting eyebolts is DIN 580. The corresponding Chinese standard is GB/T 825-1988, whose technical content is equivalent to ISO 3266:1984, Lifting eyebolts for general purposes. Give the full standard number on the order so that load capacity, dimensions and inspection requirements follow one specification.

• Shoulder (collar): the ring root is clearly thickened, which enlarges the load-carrying cross-section and spreads bending stress during the lift.
• Bearing face: the shoulder forms a flat seat, so tightening transmits the load evenly through that plane.
• Ring section: circular or nearly circular, in sizes from M8 to M100; ring bore, outer ring diameter and overall length all grow with the thread size.
• Manufacturing: integrally forged and normalized after forging, which is what qualifies the part for hoisting duty.

Typical applications are lifting points on motors, gearboxes and generators, handling interfaces on molds and tooling fixtures, and fixed lifting points on marine equipment and pressure vessels.

Because the part carries a suspended load, it follows strict handling rules.

• Axial load only: screw the eyebolt in vertically; an inclined pull of up to 45 degrees is acceptable, but transverse load is not.
• Full thread engagement: too little engagement length cuts the load capacity sharply.
• Inspection before every use: check the ring for deformation, cracks or corrosion, and scrap any eyebolt with visible damage.
• No substitution: never use a swing bolt or another eye bolt in place of a lifting eyebolt in hoisting work.

Swing Bolt (DIN 444): Pivotable Connection and Selection

The mainstream international standard for swing bolts is DIN 444 (German standard), and the corresponding Chinese standard is GB/T 798-1988. DIN 444 covers product grades A, B and C, with grade B the most precise, while GB/T 798 offers only grade C. Eye dimensions also differ systematically: at the same thread size the eye diameter of the Chinese standard is one size smaller, so parts to the two standards are not direct substitutes.

• Head: a one-piece circular ring with a smooth transition into the shank, without the step or shoulder of a lifting eyebolt. The name describes the pivoting action of the ring around the connected part, not a split construction.
• Sizes: thread range M6 to M64; grade B parts hold tighter dimensional tolerances and a better finished ring surface.

The value of a swing bolt is quick, detachable fastening. Typical uses are valve bonnets bolted to bodies for easy maintenance, pressure piping and fluid handling work where it secures pipe flanges and manhole covers, oil drilling equipment that is opened often, and joints on folding bicycles or strollers. In every case the bolt works as a fastener carrying preload and working load, not as a hoisting point.

Three checks prevent almost every mix-up in the field: read the standard marking, look at the ring root, and confirm the duty of the joint.

• No substitution: swing bolts have no lifting safety factor and no mandatory forging requirement, so they must never carry a hoisting load.
• Standard matching: when replacing swing bolts on imported equipment, confirm whether the original part is DIN 444 or GB/T 798; the different eye dimensions can cause assembly interference.
• Duty matching: swing bolts are supplied in property classes such as 4.8 and 8.8, selected for the strength of the joint. Lifting eyebolts are selected by rated load in tonnes, using the load limit table of the standard.
• Fast visual check: a thickened shoulder at the ring root means a lifting eyebolt, while a smooth ring-to-shank transition means a swing bolt.

Frequently Asked Questions

Can a DIN 444 swing bolt replace a DIN 580 lifting eyebolt for hoisting?

No. A swing bolt has no lifting safety factor and no mandatory forging requirement, so it can fracture under a hoisting load. Use only lifting eyebolts to DIN 580 or GB/T 825 for lifting work.

How do I tell a lifting eyebolt from a swing bolt without markings?

Look at the ring root. A lifting eyebolt has a clearly thickened shoulder (collar), while a swing bolt runs smoothly from the ring into the shank. Comparing ring diameter and thread size with the standard confirms the identification.

Which property classes are available for swing bolts?

Swing bolts are supplied in classes such as 4.8 and 8.8, chosen to suit the strength of the joint. Lifting eyebolts are selected instead by rated load in tonnes from the load limit table of the standard.

Are GB/T and DIN eyebolts directly interchangeable?

No. At the same thread size the eye diameter of GB/T 798 is one size smaller than that of DIN 444, so mismatched parts can interfere at assembly. Replace with the same standard as the original part.