Bolt-on lifting points look interchangeable in a catalog — eye bolts and swivel hoist rings both thread into a tapped hole and take a hook or shackle. In service they behave completely differently under angular load, and that difference is where machinery gets dropped.
Eye Bolts: In-Line Hardware
Two families: plain (non-shoulder) eye bolts are rated for straight vertical pull only — any angle at all is prohibited. Shoulder eye bolts, properly seated with the shoulder flush against a machined surface, tolerate angular loading — with brutal de-rating:
| Pull angle from vertical | Shoulder eye bolt capacity |
|---|---|
| 0° (in-line) | 100% |
| 15° | ~80% |
| 30° | ~65% |
| 45° | ~30% |
| Over 45° | Not recommended |
And the eye must be oriented in the plane of the pull — side pull across the eye plane is far worse. Shimming to orient the eye must maintain full shoulder contact and thread engagement.
Swivel Hoist Rings: Rated at Any Angle
A swivel hoist ring pivots and rotates so the bail always aligns with the pull — and carries 100% of its rated capacity at any angle. For multi-leg bridle picks on machinery, molds, and fabrications where sling angles are unavoidable, hoist rings are the engineered answer. They install with a torque wrench to the specified value (marked on the ring), which sets the preload the rating depends on — torque them every installation, not just the first.
Choosing Between Them
Vertical single-point pick from a tapped hole: shoulder eye bolt, properly seated, is economical and fine. Anything with sling angles — which is nearly every bridle lift — swivel hoist rings. Repeated production lifting: hoist rings, on inspection intervals. Rule of thumb from the de-rating table: a 45° bridle on eye bolts wastes 70% of the hardware's capacity; the hoist ring premium buys all of it back.
Thread Engagement & Inspection
Minimum engagement: 1× diameter in steel, 1.5–2× in cast iron and aluminum, per manufacturer. Retire for bent shanks, elongated eyes, damaged threads, missing markings, and hoist rings that don't swivel freely or hold torque.
Lifting Points, Sized to the Pick
Forged shoulder eye bolts and swivel hoist rings from our eye bolt collection. Thread size, capacity, and lift geometry into the quote form at the top of the page — quotes answered during business hours.