FAQs For Infrastructure Construction Bolts

A449 and A325 Flat Head Socket Cap Screws For Construction

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Top Questions And Answers For Flat Head Socket Cap Screws

What Is The Difference Between Button Head Bolts And Flat Head Bolts?

There are some similarities between button head bolts and flat head bolts. They both have a recessed, hexagonal drive hole and are driven with a hex key or Allen wrench. Their key differences are with their head style. A flat head bolt has a cone-shaped, flat head that is meant to fit countersunk with a surface. A button head socket cap screw or button head bolt that has a dome-shaped head that protrudes from the surface.

What Are The Advantages Of Flat Head Bolts?

Flat head bolt advantages come as a result of their cone-shaped head style, which can sit countersunk on tightening, They fit flush and have virtually no profile when installed into a surface. Their head style also means they self-centering. This contributes to proper seating within the material. This advantage is furthered by their recessed drive, which contributes to smoother installation.

What Are Hex Socket Flat Head Bolts?

Hex socket flat head bolts are bolts that sit flush or countersunk to an installation surface. They have a cone-shaped head that features a hex socket, which is a recessed, hexagonal-shaped drive. This socket facilitates the use of a hex key or Allen wrench for tightening. They are commonly manufactured using industrial-grade metals such as carbon steel, alloy steel, and stainless steel.

What Are Flat Head Bolts?

Flat head bolts are structural fastening devices used in applications that require a low profile or countersunk bolt. They can be installed to fit flush with the surface or just below it. They have a cone-shaped head that contributes to self-aligning properties and a recessed drive that makes them easy to install.

What Are Flat Head Bolts Used For?

Flat head bolt uses are the connection of parts that require a fastener to rest flush or countersunk to the surface of an installation. Based on their diameter, length, material, and other factors, they can be used for light duty applications, including furniture and small household equipment, as well as heavier structural applications.

What Are Flat Head Bolts Made From?

Materials used to make flat head bolts are consistent with other types of structural fasteners. They are widely available in steel, stainless steel, and similar metals. These fasteners are sometimes treated with finishes that enhance resistance to corrosion. These finishes include zinc-coating, black oxide, and hot-dipped galvanization. Nylon and other rigid polymers are also used to make flat head bolts.

What Are A325 Flat Head Bolts?

A325 flat head bolts are made to meet with ASTM A325 specifications. These specifications define mechanical properties and materials that pertain to the manufacture of heavy structural bolts. ASTM A325 bolt materials are medium carbon steel, medium carbon alloy steel, or weathering steel. Diameters ranging from 1/2 to 11/2 inches will have a defined set of mechanical properties.

How Are Flat Head Bolts Measured?

Flat head bolts are primarily measured by their length, diameter, head angle, and head height. The diameter measurement is taken in the same way as other types of bolts. The length, however, includes the head and the rod in one measurement. If the bolt has an unthreaded portion of the shaft, that is taken as separate measurement. The recess in the center of the head is the drive size measurement.

How Are Flat Head Bolts Installed?

Flat head bolts are installed directly into a workpiece through a pre-drilled hole. It can also be installed by attaching a nut. The recessed drive in the head allows for uniform tightening with hand-operated and electrical tools, which are inserted into the drive. The conical head should be flush with the installation surface or sit slightly countersunk.

Are Flat Head Socket Cap Screws And Flat Head Bolts The Same Thing?

Socket head cap screws and flat head bolts primarily differ because of their head styles. Socket head cap screws are characterized by their cylindrical head, which has a diameter that is slightly larger than that of the shaft. Flat head screws feature a cone-shaped or conical head extending from the neck of the bolt at a set angle. Both of these fasteners feature a recessed drive.