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Types and Uses of Wood Screws

If you're unsure of the types of wood screws available or you need the answer to which wood screws do I need for certain projects, then you have come to the right place. This guide looks at the different types of wood screws you can buy, when to use them and how to use them, and how to do so correctly for your DIY project.

What Are Wood Screws?

Wood screws are used for the connection of wood materials to help keep them secure. Wood screws can be used with MDF, chipboard, softwood, and hardwood. There are a range of different types of wood screws to choose from, each one with its own features, such as twin threads for effective drive and shanks to avoid wood splint.

Wood screws come in various drive types and head shapes, and these days the modern wood screw has a shank of uniform size to the head, meaning you don't always need to drill a pilot hole compared to older wooden screws, which were typically made from brass or steel.

Wood Screws Sizes

It is highly important that you use the correct type of wood screw and the right size to help you support the weight of the road and provide stability. The thickness of the screw needs to correspond with the thickness of the wood.

A number is applied to the diameter or gauge of the screw to help you identify the correct size. The most common sizes of wood screws are 6, 8, and 10. The numbers increase to represent the thickness of the wood, i.e., the higher the screw number, the thicker the wood. Size 8, for example, is commonly used for general purposes, while a number size is preferable for fine woodworking.

Wood Screw Types

Wood screws come as either partially or fully threaded steel screws. Steel is preferred for wood screws because of their strength and durability. They also feature a pointed tip for precision and can withstand high-powered drilling and driving, and the threads of the screw wrap around the shank to enable them to be securely driven into the wood.

Wood Screw Head Types

Wood screw heads come in various drives and shapes, which will be detailed below.

The most common drives are;

  • Slot Head Screws - The most common type of screw can be used with a flathead screwdriver to drive into the wood material.
  • Phillips Head Screws - These have greater functionality than flathead screws and can be driven into a wide variety of different materials. However, when the final section of the screw is being driven into the wood, there is often some slipping, which can damage the screw head and the wood.
  • Square Drive or Robertson Screws - The square head of these screws is advantageous over the Phillips screws as it reduces the risk of slipping. These heads are typically found on pocket screws.
  • Starhead Screws - These are becoming more popular due to their reliability and the ability to accommodate higher amounts of torque.

Moving onto the more common types of wood screw heads, the options include the following,

  • The Countersunk Head Wood Screw

Featuring a canonical-shaped head, the countersunk head screw can be secured in the wood so it sits flush with or underneath the surface. The countersunk head cross surface can vary from 60° to 120° in diameter.

  • Hex Head Wood Screws

Ideal for fixing wooden materials designed for heavy loads, e.g., roofing, timber construction, and landscaping, the hex head wood screw is available in many different widths, which enables the screw to give added protection from corrosion.

  • Round Head Wood Screws

Round-head wood screws will have a double countersunk head and are known for being particularly easy and quick to drive. They are ideal for insertion with a carpenter's screwdriver.

Wood Screw Materials

As touched upon above, wood screws come in different materials. While steel is often the preferred material of choice for modern usage, other materials might be more likely to suit your needs.

  • Brass Wood Screws

Brass wood screws are available in round, raised, and countersunk heads. Typically used for their visual appeal, they are more common for external uses due to their ability to resist corrosion. They are also ideal for use with naturally acidic wood compared to steel screws and for ironmongery purposes too.

  • Stainless Steel Wood Screws

Stainless steel screws offer a good level of corrosion resistance and are often used in places with excess levels of moisture, i.e., bathrooms. Stainless steel wood screws come in various head types and are compatible with screwdrivers, impact drivers, and combi drills to make them perfect for a range of materials and uses.

  • Steel Wood Screws

Steel wood screws can be applied without the need for a pilot hole, and you can purchase them in different styles and sizes. If you want steel screws to be more durable and corrosion-resistant, look for hardened steel screws or zinc-plated steel wood screws for added protection and benefits.

Wood Screw FAQs

How Long Should A Wood Screw Be?

General guidelines state that you should ensure the screw can penetrate at least half of the thickness of the base material. The screw also needs to secure two boards together safely with no protrusion. Other factors, including the wood, screw material, and lateral and shear forces, will dictate the length of the screw.

How Much Weight Will Wood Screws Hold?

Wood screws can potentially hold up to 100 lb. This is dependent on the type of screw used, and it needs to be attached to purpose-built wood studs.

Do You Need Pilot Holes for Wood Screws?

It is recommended that you drill appropriately sized pilot holes for the screws you are inserting into the wood. This will stop the wood from splitting or cracking and will enable you to guide the screw through the wood with ease into the right place. If a pilot hole isn't made beforehand, there is a significant risk of damage to both the screw and the wood.

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