Eye bolt capacity chart: DIN 580, BS 4278, JIS and US eye bolts by thread size

Eye bolt ratings are the least portable numbers in rigging. The same thread size is rated very differently under DIN, British, Japanese and US standards, and every one of those ratings falls — or disappears — when the pull leans away from the bolt’s axis. The charts below are grouped by standard, so the figure you read is the one for the bolt in your hand.

/01DIN 580 eye bolts and DIN 582 eye nuts.

DIN 580 eye bolts and DIN 582 eye nuts share one rating per thread size. Each bolt is rated for three directions: a vertical pull, a pull at up to 45° in the plane of the eye, and a pull at up to 45° across it (sideways). Ratings are per bolt, in kilograms.

The angled columns are given here for M8 to M42, where we have checked them against the DIN 580:2018 user information. Above M42 the angled ratings are in the maker’s instructions supplied with the bolt. There is no rating for a pull at 90° to the eye: the standard says such a pull must not be applied. The ratings hold from −20 °C to 200 °C.

/02Same thread, different standard.

At M20 the three standards give 630, 1,200 and 1,600 kg. All three are correct; they are different designs, steels and rating rules. A bolt marked with one standard is never lifted on another standard’s table — and a metric collar eye bolt is never assumed to match a US machinery eye bolt of a similar thread.

/03US shoulder and machinery eye bolts, by angle.

US-pattern shoulder nut and machinery eye bolts are rated in pounds for an in-line pull, then reduced as the pull leans away from the bolt’s axis. The reduction is 80% at 15°, 65% at 30°, 30% at 45° and 25% at 90°, applied in the plane of the eye. Our shoulder nut, machinery and regular nut eye bolts carry the same in-line rating at each nominal size:

The kilogram figures are our conversion of the pound ratings, rounded down. Load the eye in its own plane — turn it to face the pull, with a shim under the shoulder if needed — and never reeve one sling through two eye bolts.

/04US eye nuts.

/05What every rating assumes.

Worked example: a 1.6 t gearbox has two DIN 580 tapped holes, and a two-leg sling will hang at about 40° from vertical in the plane of the eyes. Each bolt takes half the weight, pulled at an angle, so each must be rated at least 800 kg in the ≤45° in-plane column. M20 gives 860 kg — enough. M16 gives 500 kg — not enough, though its 700 kg vertical rating might suggest otherwise.