Marine Wood Screw & Bolt

Our wood screws used in marine applications typically feature sharp, coarse threads that are widely spaced. These screws are designed to create their own mating threads during installation, eliminating the need for a nut or tapped hole. They often have a gimlet point, which is a threaded cone point with a point angle of 45 to 50 degrees, allowing them to easily thread into wood.

There are two types of wood screws: those with cut threads and those with rolled threads. Wood screws with cut threads are tapered and have about two-thirds of their length threaded, leaving one-third as an unthreaded section called the body. On the other hand, wood screws with rolled threads are not tapered and have at least four times the basic screw diameter (or two-thirds of the nominal screw length, whichever is greater) threaded.

For screws with cut threads, the thread crest diameter is no larger than the body diameter, and the body diameter is larger than same-sized screws with rolled threads. In contrast, screws with rolled threads have a thread crest diameter larger than the body diameter, and the body diameter is smaller than same-sized screws with cut threads. The presence of an unthreaded body helps prevent two wood pieces from separating as they are screwed together.

In terms of installation, wood screws are typically turned clockwise (right-hand threading) to drive them into the wood securely.

The Size Of Marine Wood Bolt and Screw

Marine wood screws come in various sizes to accommodate different applications and levels of duty. Here are the size ranges and typical uses for each size:

• #4: Designed for small crafts, jewelry boxes, attaching hinges, etc. These screws are very light duty and available in lengths ranging from 3/8″ to 3/4″.
• #6: Suitable for small crafts, hinges, drawer slides, light-duty jigs and fixtures, and similar applications. They are light duty and available in lengths ranging from 1/2″ to 1-1/2″.
• #8: Ideal for general furniture construction, cabinets, and light construction projects. These screws are considered good all-purpose options. They are available in lengths ranging from 5/8″ to 3″.
• #10: Suited for general construction, heavy-duty furniture, outdoor projects, decks, boat building, and other similar applications. These wood screws are available in lengths ranging from 3/4″ to 4″.
• #12 & #14: Intended for heavy-duty construction tasks, such as hanging solid-core doors. These large wood screws come in selected styles and are available in lengths ranging from 3/4″ to 6″.

The Head Type Of Marine Bolt

In marine woodworking, there are three common head types for wood screws: flat (countersunk), oval (countersunk), and round. Here are some details about these head types:

• Flat Head: Flat heads are the most popular choice in marine applications. They have an 82° conical bearing surface and, when countersunk, the head sits flush with the mating surface. This makes them ideal for applications where a flush and concealed finish is desired. Flat head screws can be easily concealed using color-coordinated plastic screw covers. If the head is sufficiently countersunk, a filler or wood plug can also be used to cover the bolt head.
• Oval Head: Oval heads are also countersunk, but they have a slightly different shape compared to flat heads. They are considered decorative and are often left exposed in marine woodworking projects. Oval head screws offer a visually appealing finish and can add a decorative touch to the overall design.
• Round Head: Round heads have a fully rounded shape and are not countersunk. They are primarily used for decorative purposes in marine woodworking. Round head bolts are often left exposed to showcase their unique design and can contribute to the aesthetic appeal of the finished project.

Marine Grade Wood Screw Material

In marine applications, wood screws are available in different materials, each offering varying levels of corrosion resistance and physical strength. Here are the common materials used for marine wood screws:

• Unhardened Steel (Zinc Plated): Unhardened steel bolts are often zinc plated to provide moderate corrosion resistance. Zinc plating helps protect the steel from rust and corrosion. However, in marine environments, where exposure to saltwater is common, unhardened steel screws may not offer sufficient protection against corrosion.
• Stainless Steel: Stainless steel wood screws are highly recommended for marine applications due to their superior corrosion resistance. They are particularly resistant to rust and corrosion caused by exposure to saltwater. Stainless wood bolts are available in different grades, such as 304 and 316, with 316 stainless steel being more corrosion resistant and suitable for more demanding marine environments.
• Brass: Brass wood screws provide better corrosion protection compared to zinc-plated steel. They are often used in marine applications where moderate corrosion resistance is required. Brass is a softer material compared to steel, which can affect its physical strength. However, it is still suitable for many marine woodworking projects.
• Silicon Bronze: Silicon bronze screws are known for their excellent corrosion resistance in marine environments. They offer superior protection against rust and corrosion, making them a preferred choice for marine applications. Silicon bronze bolts are recommended when working with pressure preservative-treated wood, such as “AcQ” (Alkaline Copper Quaternary). They are nonmagnetic and provide good physical strength.

Marine Wood Screw Parameter