Eye Bolt Shoulder Type
When is a shoulder eye bolt mandatory?
A shoulder eye bolt is mandatory whenever any angular or side loading is anticipated, including any use with sling angles (bridle slings, multi-leg lifts) or when the load may tilt or rotate during hoisting. Guidance states: 'If you are lifting with slings at ANY angle, you must use a shouldered eye bolt.'
What is the typical angular capacity and derating for shoulder eye bolts?
Typical derating: 0° (vertical) = 100% WLL; 15° = ~80%; 30° = ~50%; 45° = ~25-30%. Beyond 45° is not permitted. Some instructions prohibit angles below 30° unless approved by the manufacturer. Always use the specific manufacturer's angular WLL chart.
How should a shoulder eye bolt be oriented relative to the load?
Loads must be applied in the plane of the eye, not at an angle to this plane. The eye should be positioned so the sling or shackle pin aligns with the eye's plane. Side-loading across the plane reduces capacity and risks failure; reposition the bolt or use swiveling hardware instead.
An Eye Bolt Shoulder Type is a forged, threaded lifting device with an integral shoulder between the eye and shank that seats flush against the mounting surface. It is rated for vertical and angular loading up to 45° from vertical, with derated Working Load Limits. Only shoulder eye bolts are permitted for angular loads in rigging, unlike plain eye bolts which are limited to vertical lifts.
On a manufacturing shop floor, shoulder eye bolts serve as engineered lifting points for machine components, dies, molds, and assemblies. They are essential for multi-point lifts with slings at angles, such as bridle slings or spreader beams, and for rotating or tilting loads. Installation requires full thread engagement and flush seating of the shoulder against the surface. Sling angles must be controlled, with derating applied: 100% WLL at 0°, ~80% at 15°, ~50% at 30°, and ~30% at 45°. Pre-use inspection checks for cracks, deformation, and proper orientation in the load plane. Compliance with manufacturer charts and competent person oversight is critical for safety.
Using non-shoulder (plain) eye bolts for angular or side loads, which causes bending moments and catastrophic failure; only shoulder eye bolts are permitted for angular loading.
Shoulder not fully seated due to insufficient thread engagement, soft surfaces, or incorrect washers, leading to thread bending and reduced capacity.
Ignoring angle derating by using vertical WLL for angled lifts, overloading eye bolts at 30-45° where capacity drops to 30-50% of vertical rating.