FAQs For Infrastructure Construction Bolts

A449, A307, Stainless And Domestic Round Head Bolts For Construction

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Top Questions And Answers For Round Head Bolts

Where are round head bolts used?

Round head bolts are a good choice for light-duty or standard-duty connections of wood to wood or wood to metal. Projects that involve the connection of wooden infrastructure pieces commonly employ round head bolts unless the structure must bear a very heavy load. They also secure fencing and guardrails properly.

What is the difference between round head bolts and carriage bolts?

Round head bolts and carriage bolts share some similarities except that a carriage bolt has a square-shaped neck. The square neck beneath the head of a carriage bolt stops the fastener from turning after it has been tightened. Beyond this feature, both types of bolts are capable of many of the same functions.

What are the advantages of round head bolts?

Round head bolts perform well as fasteners in heavy-duty structural connections of wood pieces. They feature dome-shaped heads with enough surface area to distribute force like washers. This enables them to eliminate the use of washers during construction. They are also appropriate for many light-duty connections in wood structures.

What are round head bolts?

Round head bolts distribute force effectively without the need to include a washer. They are highly effective when making wood-to-wood structural connections. Their dome-shaped heads have low profiles and leave the surface relatively smooth upon installation. Beneath the head, a cylindrical neck extends into a fully threaded shaft.

What are round head bolts made from?

Medium-carbon steel and low-carbon steel are standard industrial materials used in the manufacturing of round head bolts. Hot-dip galvanization is also applied on select bolts to resist corrosion. Rigid and strong ASTM A449 bolts are made from medium-carbon steel. ASTM A307 round head bolts are produced from low-carbon steel.

What are ASTM standards for round head bolts?

Round head bolts follow ASTM standards that specify mechanical properties, size, and material. Medium-carbon steel is used to manufacture ASTM A449 round head bolts. Low-carbon steel is the material found in ASTM A307 bolts. Diameters for either type range from 1/2 to 1-1/4 inches. They have lengths from 6 to 18 inches.

How long are round head bolts?

Round head bolts in lengths of 6 to 18 inches are made for fastening metal to wooden structural pieces during construction. These long lengths reach through the thick pieces of wood. For non-industrial applications, round head bolts shorter than 6 inches are appropriate when fastening light structural pieces or repairing equipment.

How are round head bolts measured?

Sizing of round head bolts follows the same methods as for other structural bolts. Diameters are measured across the thickness of the shaft with the threads included. Length is measured from the end of the threaded shaft to directly beneath the head. The pitch of threading and the number of threads per inch determine thread measurements.

How are round head bolts installed?

Round head bolts have smooth, dome-shaped heads. They cannot be loosened or tightened by the head, like a hex or socket head bolt. Installation involves putting them through pre-drilled holes and then threading a nut onto the end of the bolt. All tightening and loosening takes place by adjusting the nut.

Are round head bolts and button head bolts the same?

Round head bolts differ from button head bolts and screws although they might work interchangeably at times. Button head bolts have a rounded head with a higher profile and recessed drive. Round head bolts have a lower-profile, dome-shaped head and no recessed drive. They are tightened with a nut.