ASTM A449 Configurations

Hex Bolts

One of the most common A449 fasteners is a standard hex head bolt. These bolts vary in length and are typically used for a variety of generic applications.

A449 fasteners are also commonly made as heavy hex bolts. These bolts are often short in length due to commonly being used in structural applications, however, there is no length limitation and they can be made to any requirement a project has. The heavy hex pattern is larger than the standard hex head. Dimensional requirements for heavy hex bolts are covered under the AMSE B18.2.1 specification.

Hex and Square Lag Screws

Hex and square head lag screws are manufactured when A449 is required. These fasteners are generally used in timber applications where the bolt is screwed into a slightly smaller pilot hole in the wood to create tension and prevent the bolt from loosening. The square head was historically used before hex heads were created. These are often used in restoration projects to maintain the historical integrity of the project.

Step Bolts

A449 is the primary grade for step bolts. These bolts are used as literal steps on steel communication and electrical transmission towers. The bolts usually come with two heavy hex nuts and are often 6”-10” in length.

Carriage Bolts

Carriage bolts have a round head with a square neck and are not readily available in A449 material but can be custom manufactured. These fasteners are typically used in wood connections and the square neck prevents the bolt head from turning.

Thread-Each-End Rods

A449 can be manufactured as a rod with threads on each end. Typical uses for these rods include anchor rods that will be embedded into concrete, marine applications, and wood applications.

Rods/Studs

One of the most readily available forms of A449 is a fully threaded stud. These rods, measured from first thread to first thread, are commonly used in flange joints. Fully threaded rods have more generic applications and can be used in a variety of projects.

U-Bolts

Another configuration for A449 is U-bolts. Both round-bend and square-bend U-bolts are used to install piping systems. They are also commonly used to hang wrought iron pipes in mechanical systems and sometimes they are embedded in concrete to be used as anchor bolts.

Eye Bolts

High-strength eye bolts are sometimes required in A449 material. Often used in rigging applications, these fasteners can have forged eye holes or bent eye holes that are either open or welded closed.