FAQs For Infrastructure Construction Bolts

Galvanized, HDG, A307 And Domestic Timber Bolts For Construction

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Top Questions And Answers For Timber Bolts

Why do timber bolts have fins?

The fins on the underside of a timber bolt’s head are used to help maintain the security and stability of the installation. These fins or nubs bite into the surface of the timber and prevent the bolt from turning once it has been tightened. Most timber bolts will have two or four, which are positioned in a parallel arrangement.

What are timber bolts?

A timber head bolt is a fastening element that’s used to connect timber-based structures, including decks, docks, sheds, framing, playground equipment, and more. They feature an oversized, dome-shaped head that has a smooth, low profile. These fasteners also have nubs or fins that bite the surface of the timber just below the head, thereby ensuring better stability.

What are timber bolts used for?

Timber bolts are most commonly used in timber-based structural joints. They fasten wood-to-wood connections, especially those used in exterior applications, like docks, boardwalks, decks, timber framing, and more. They are made to be economical and resistant. Although they are primarily used with lumber, they are sometimes installed into heavy machinery.

What are timber bolts made of?

Timber bolts are made from structural-duty materials that include carbon steel and stainless steel. The material spec associated with these fasteners is A307 grade A. This type of carbon steel is typically hot-dipped galvanized to safeguard against corrosion. Stainless steel is also an acceptable material for timber bolts that are inherently corrosion resistant.

What are timber bolt measurements?

The main measurements of timber bolts are their diameter and length. The diameter is the thickness of the shaft. The length will include the shaft and the threaded portion. Other measurements of timber bolts include the head diameter and the length of just the threaded portion, which is also called the thread length.

How are timber bolts installed?

Timber bolts are meant to be installed into pre-drilled holes in timber-based structural elements. They are fastened from the nut side, which can be completed with a hex-shaped tool, like a wrench. Sometimes timber bolts are installed directly into the hole and simply tightened until the fins bite into the material. They can also be paired with special inserts.

Do timber bolts need a washer?

Timber bolts should be installed without a washer placed below the head. The head itself is wide and dome-shaped and is effective for evenly distributing force. A washer would also interfere with the fins or nubs that are meant to grip or sit within the surface of the timber. A washer may be placed on the nut side of the assembly.

Are timber bolts and economy bolts the same?

Timber bolts are the same as economy bolts. Both terms are used to refer to the same fastener, which is used to assemble timber-based joints in various types of structures. “Economy bolt” is a more common usage in the Pacific Northwest. These bolts are also called dome head bolts, fender head bolts, mushroom head bolts, and safety head bolts.

Are timber bolts and carriage bolts the same?

Timber bolts are closely related to carriage bolts, but they have a few different features and are used in different types of applications. Timber bolts have a larger, broader head with small nubs or fins on the underside. These bolts are meant to connect wood to wood structural parts. Carriage bolts have a square neck and are intended for use in fastening wood to metal parts.

Can timber bolts be used in pressure-treated wood?

Timber bolts are acceptable for use in pressure treated wood if they are made from corrosion-resistant materials or treated with resistance-enhancing finishes. This is why timber bolts are most often made from stainless steel or carbon steel with hot-dipped galvanization. Similar materials and treatments should be used for other parts in the timber bolt assembly if that assembly will be used to fasten pressure-treated wood.