Eye Bolts

1. What is an eye bolt and what is it used for?

An eye bolt is a fastener featuring a looped head (the “eye”) and a threaded shank, designed to provide a secure attachment point for ropes, cables, chains, or shackles. They are commonly used for lifting, rigging, hoisting, towing, and anchoring applications across industries such as construction, manufacturing, marine, and industrial settings.

2. What are the different types of eye bolts?

There are several common types of eye bolts, including:

• Shoulder eye bolts – Have a shoulder beneath the eye, allowing for angular loading.
• Non-shoulder (plain) eye bolts – Designed for vertical (in-line) loads only.
• Machinery eye bolts – Feature a longer shank for use in tapped holes.
• Screw eye bolts – Have wood-screw threads for use in wood.
• Eye lag bolts – Used for heavy-duty wood applications.
• Welded eye bolts – Forged or welded for added strength under load.

3. How much weight can an eye bolt hold?

The load capacity of an eye bolt depends on its size, material, type, and the angle of the load. For example, a 1/4″ shouldered eye bolt may safely lift around 650 lbs in a vertical pull, while a 1″ version can handle several thousand pounds. Always check the manufacturer’s Working Load Limit (WLL) and remember that angled loads significantly reduce capacity—a 45° angle can reduce capacity by up to 70%.

4. What is the difference between a shouldered and non-shouldered eye bolt?

• Shouldered eye bolts have a forged collar at the base of the eye, allowing them to handle angular loads (when properly tightened against the mounting surface). They are safer and more versatile for rigging.
• Non-shouldered eye bolts should only be used for straight, vertical lifts. Side loading these bolts can bend or break them, leading to dangerous failures.

5. How do I properly install an eye bolt?

To safely install an eye bolt:

1. Ensure the bolt is the correct size, material, and type for your application.
2. Inspect for cracks, deformation, or thread damage before use.
3. Drill or tap the hole to a depth that allows full thread engagement (typically 1.5x the bolt diameter for steel).
4. Tighten the eye bolt fully so the shoulder (if shouldered) sits flush against the surface.
5. Align the eye in the direction of the load whenever possible.
6. Never use washers under shouldered eye bolts to align them—use spacers below the shoulder if needed.

6. What materials are eye bolts made from?

Eye bolts are commonly manufactured from:

• Carbon steel – Strong and economical, often used in industrial settings.
• Stainless steel (304 or 316) – Corrosion-resistant, ideal for marine and outdoor use.
• Galvanized steel – Coated with zinc for added rust resistance.
• Forged alloy steel – Provides the highest strength for heavy lifting applications.

The choice of material depends on the environment, load requirements, and exposure to corrosive elements.