Eye Nuts & Swivel Lifting Nuts | Crosby & Codipro

When a heavy load such as an electric motor, pump, or machined casting is manufactured with an exposed threaded stud rather than a tapped hole, standard eye bolts cannot be used. Eye Nuts (also known as lifting nuts) are the engineered solution. Featuring a female thread, these forged rings screw directly onto the protruding stud, creating an instant, secure attachment point for your rigging hooks and shackles.

Holloway Houston Inc. (HHI) supplies certified eye nuts for critical lifting applications. We stock standard forged carbon steel models from Crosby alongside highly specialized, multi-directional swivel nuts from Codipro. With Working Load Limits (WLL) up to 22,500 lbs and tap sizes ranging from 1/4" to 2", our inventory ensures your lifting operations remain compliant and secure.

The Eye Nut Product Ecosystem

1. Standard Forged Eye Nuts (Crosby G-400)

The classic solution for straight-line, vertical lifting.

• The Design: The Crosby G-400 is forged from carbon steel, Quenched and Tempered for maximum toughness, and hot-dip galvanized to resist corrosion.
• Application: Ideal for static, straight vertical lifts where the load is balanced and the pull is directly in-line with the threaded stud.
• Capacities: Available in a wide range of tap sizes (1/4" to 2") offering Working Load Limits from 520 lbs up to 22,500 lbs.

2. Swivel Eye Nuts (Codipro FE-SEB)

The modern, fail-safe solution for angular lifting.

• The Problem with Standard Nuts: Just like a standard eye bolt, a rigid eye nut loses significant capacity if it is side-loaded (pulled at an angle).
• The Codipro Solution: The FE-SEB (Female Swivel Eye Bolt) operates exactly like a swivel hoist ring. It features a female-threaded base that threads onto the stud, while the lifting ring itself can pivot 180° and swivel a full 360°.
• The Benefit: Because the ring aligns with the direction of the sling, the FE-SEB maintains its full rated Working Load Limit at any pull angle.
• Capacities: Available with high-performance WLLs up to 13,800 lbs (at a 4:1 safety factor) and 12,200 lbs (at a 5:1 safety factor).

Safety Guidelines for Eye Nuts

Using an eye nut requires careful attention to thread engagement and load geometry to prevent shear failure.

1. Flush Seating is Mandatory

An eye nut must be threaded down completely so that its base sits 100% flush against the surface of the load. If the stud is too long and the nut bottoms out on the threads before touching the load surface, it can bend or snap under tension. Use structural washers (shims) if necessary to ensure a flush, tight fit.

2. Full Thread Engagement

Ensure the threaded stud fully engages the entire depth of the eye nut. The stud must be of sufficient grade (usually Grade 8 / Class 10.9 or better) to support the rated capacity of the nut.

3. Angular Loading Rules

• Crosby G-400: Designed primarily for in-line lifts. If you must use a standard eye nut for an angular lift (e.g., using a multi-leg bridle sling), the WLL must be drastically reduced according to the manufacturer's charts, and the pull must be in the plane of the eye.
• Codipro FE-SEB: If your lift requires sling angles or flipping the load, you must upgrade to a Swivel Eye Nut.

Technical Specifications

• Tap Sizes: Imperial (UNC) sizes from 1/4" up to 2".
• WLL Range: 520 lbs to 22,500 lbs.
• Safety Factors: Available in 4:1 and 5:1 design factors depending on the specific model and manufacturer.
• Materials: Drop Forged Carbon Steel (Crosby) and High-Tensile Alloy Steel (Codipro).
• Standards: Meets or exceeds the performance requirements of ASME B30.26 (Rigging Hardware).

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