Swivel and Snap Hook Types for Rigging Applications

Rigging Connection Hardware

Swivels and snap hooks are connection hardware used to join rigging components while allowing rotation, quick connection/disconnection, or both. While they may seem like simple accessories, selecting the wrong type or size can create a weak link in your rigging system.

Swivel Types

Eye-Eye Swivel

Two eye loops connected by a rotating joint. Allows 360° rotation between connected components, preventing twist buildup in wire rope, chain, or synthetic slings.

• WLL range: 1,000-50,000+ lbs
• Best for: Between a crane hook and sling assembly, preventing sling twist
• Caution: Must be rated for the load. Cheap hardware store swivels are NOT rigging-grade.

Jaw-Eye Swivel

One end has a clevis jaw (with pin) and the other has an eye loop. The jaw connects to flat fittings, chain links, or anchor points while the eye accepts hooks or shackles.

Eye-Hook Swivel

An eye on one end and a hook on the other, with a rotating joint between them. Commonly used at the end of wire rope assemblies.

Bearing Swivels (Ball Bearing)

Heavy-duty swivels with internal ball bearings for smooth rotation under load. Used in applications requiring continuous rotation (rotating platforms, spreader bars, pile driving).

• Advantage: Rotates freely even under full rated load
• Cost: 3-5× more than standard swivels
• Best for: Crane blocks, rotating hooks, pile driving swivels

Snap Hook Types

Standard Snap Hook

A hook with a spring-loaded gate that snaps closed when released. The gate prevents the attached item from falling off the hook during normal use.

• Gate types: Wire gate (lightest), stamped gate (most common), locking gate (most secure)
• WLL range: 500-10,000 lbs depending on size and material
• Limitation: Standard snap hooks can open if the gate is pressed against an object (gate roll-out). NOT recommended for overhead lifting unless locking type.

Self-Locking Snap Hook

The gate includes a twist-lock, slide-lock, or double-action mechanism that prevents accidental opening. Required by OSHA for fall protection applications (29 CFR 1926.502(d)(6)).

Swivel Snap Hook

Combines a snap hook with an integral swivel eye, providing both quick connection and rotation. Common on lanyards, leashes, and light-duty rigging.

Material Options

Material	Strength	Corrosion Resistance	Weight	Cost	Best For
Forged alloy steel	Highest	Poor (requires plating)	Heavy	Moderate	Overhead lifting, heavy rigging
Stainless steel 316	Moderate	Excellent	Heavy	High	Marine, food processing
Zinc-plated steel	Good	Good	Heavy	Low	General industrial
Bronze	Low	Good	Heavy	High	Marine, non-sparking
Aluminum	Low	Good	Light	Moderate	Fall protection, light duty

Selection Criteria

• Overhead lifting: Use forged alloy steel with safety latches. Must be proof-tested and marked with WLL.
• Fall protection: Self-locking snap hooks required per OSHA. Must be compatible with the D-ring size (no roll-out possible).
• Marine: Stainless steel 316 or bronze for saltwater corrosion resistance.
• Quick-connect rigging: Snap hooks for frequent connection/disconnection. Shackles for permanent connections.

Inspection Criteria

• Gate must close completely and latch positively
• Spring must return the gate to closed position when released
• Locking mechanism (if equipped) must engage fully
• No visible cracks, bending, or deformation in the hook body
• Throat opening must not exceed 10% of original dimension
• Swivel must rotate freely without binding
• WLL marking must be legible

Common Mistakes to Avoid

Avoiding these common errors can prevent equipment failure, regulatory violations, and serious safety incidents in the field.

• Side-Loading a Shackle: Shackles are designed for in-line loading only. Side loads perpendicular to the pin axis can reduce capacity by 50% or more and cause deformation or failure without warning. Use the correct shackle type and orientation.
• Using Regular Eye Bolts at an Angle: Standard unshouldered eye bolts are rated only for vertical loading. At 45 degrees, capacity drops to zero. Only shouldered eye bolts can handle angular loads, and even then capacity at 45 degrees is only 25% of vertical rating.
• Over-Torquing Turnbuckle Bodies: Using pipe wrenches or cheater bars on turnbuckle bodies can twist and weaken the frame. Adjust by hand or with proper tools. Over-rotation can pull threads out of engagement.
• Failing to Use Cotter Pins or Lock Nuts: Vibration can cause shackle pins, turnbuckles, and threaded connections to loosen. All critical connections must be secured with cotter pins, lock wire, or lock nuts to prevent complete rigging failure.
• Not Accounting for Dynamic Loads: Static load calculations do not account for wind, vibration, impact, or swinging loads that can multiply forces by 2-4 times. Apply a dynamic load factor of 2.0 for moderate shock and 3.0 for heavy shock applications.