An eye bolt is a screw-like fastener with a loop on one end and screw-type threads on the other end. They come in a variety of product designs to accommodate different load weights and shapes. They are primarily used to attach cables or wires to objects. Load limits are factored at a 4-to-1 ratio of load-pounds against bolt diameter size.

The most common eye bolt types include wire, forged, and machinery and the most common eye bolt materials include stainless steel, titanium, zinc, and custom alloys. Consider the following information when selecting an eye bolt:

1. Wire eye bolts are used for straight vertical load-lifts that are increased gradually. They should not be used for angular load-lifts. Wire eye bolts are usually offered in zinc-plated or stainless steel materials.
2. Like wire eye bolts, forged eye bolts best accommodate vertical lifts that are increased gradually. Unlike wire eye bolts, standard forged stainless eye bolts may be used for angular load lifts only if the bolt design includes a "properly seated" shoulder. Forged eye bolts are available in larger sizes than wire eye bolts. These are usually hardware-grade stainless steel eye bolts.
3. Like the wire and forged eye bolts, machinery eye bolts best accommodate gradually increased vertical load-lifts. Machinery galvanized eye bolts, however, have a higher load limit safety factor (5-to-1) than the prior two bolt styles. Like forged eye bolts, the machinery eye bolts may be used for angular lifts with the proper shoulder design. A corrosion-resistant hot-dipped galvanized eye bolt is a common variety.

Action Steps
The best contacts and resources to help you get it done

Find eye bolt manufacturers or distributors in your area

Visit an online business directory to find suppliers of industrial eye bolts in your city or state.

I recommend: ThomasNet, a major business resource website, offers a long list of eye bolt manufacturers and distributors throughout the US. The IQS (Industrial Quick Search) Directory is another online resource of eye bolt manufacturers.

Find the right eye bolt for the right job

Read information concerning work load limits and dimensions for the most common eye bolt styles.

I recommend: The BoltDepot offers charts and product diagrams with load limits and dimensions, in addition to selling bolts in a variety of materials and styles. Grainger offers even more eye bolt diagrams and specs.

Use industrial eye bolts safely, especially when rigging loads

Safety is a critical issue, particularly if the eye bolt's individual preload stress capacity is exceeded during normal usage and subject to shear force failure.

I recommend: The Canadian Centre for Occupation Health and Safety offers safety tips while using eye bolts for lifting loads as does WorkSafe Saskatchewan. (Note that both of these are Canadian government websites.) Hoist and crane rigging safety guidelines are offered by Texas A&M's Engineering Program (PDF).

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Eye bolt manufacturers may offer made-to-order custom designed eye bolts.
• •  Do not use plain or shoulder-less eye bolts for loads that are at a load-angle of 45-degrees or less.
• •  Do not use an eye bolt that isn't 'plainly marked' with information that relays the individual bolt's load-limit.
• •  When using shoulder-designed eye bolts, the bolt must be screwed into the load at a depth where the shoulder fits flat and tight with the load.
• •  Do not use eye bolts that have been cut, welded, brazed, or otherwise altered.