What Size Drill Bit for #8 Screw: Your Ultimate Guide to Perfect Drilling

When embarking on a drilling project, one of the pivotal questions you might find yourself asking is, “what size drill bit for #8 screw should I use?” Indeed, making the correct choice in drill bit size is essential for achieving the desired outcome. In this guide, we delve deep into the various aspects that dictate the ideal drill bit size for a #8 screw in different materials.

Understanding the #8 Screw Size

Before we venture into the specifics of choosing the right drill bit size, let us first familiarize ourselves with the #8 screw. This common screw size is renowned for its versatility in different applications, thanks to its flat or oval head types. The screw boasts a shank diameter of 0.164 inches and a thread size of 32 threads per inch, rendering it suitable for a range of materials including wood, plastic, and sheet metal.

Screw SizeHard WoodSoft WoodCountersink Size
Tapered BitStraight BitTapered BitStraight Bit

The Importance of Choosing the Right Drill Bit Size

Selecting the right drill bit size isn’t just a matter of precision. It is a critical step to ensure the longevity and stability of your project. Additionally, using the correct drill bit size can prevent the material from splitting, thus maintaining its integrity.

Metal Drilling: The 11/64” Solution

When it comes to metal drilling with a #8 screw, experts recommend a drill bit size of 11/64″. This size ensures that the screw fits perfectly, providing a sturdy and reliable hold.

Wood Drilling: Distinguishing Between Hard and Soft Wood

For wood drilling projects, the drill bit size can vary based on the type of wood in question. In hard wood, an 11/64″ tapered bit or a 1/8″ straight bit would be ideal, while in soft wood, you would be looking at a 5/32″ tapered bit or a 7/64″ straight bit.

Creating the Pilot Hole

Creating a pilot hole before inserting a #8 screw is a step that can’t be skipped. It not only ensures proper alignment but also prevents the wood or metal from splitting. The recommended countersink size for a #8 screw is 3/8”.

The Right Screwdriver for #8 Screw

Equally important as selecting the right drill bit is choosing a screwdriver that matches the #8 screw size. Ensure you have a screwdriver that corresponds well with the screw head to facilitate easy driving of the screw.


Q1: Can I use a #8 screw for all materials?

A: The #8 screw is versatile and can be used in various materials, including wood, plastic, and sheet metal. However, always ensure to choose the right drill bit size for the material at hand.

Q2: What is the shank diameter of a #8 screw?

A: The shank diameter of a #8 screw is 0.164 inches.

Q3: What is the role of a pilot hole, and how do I create one?

A: A pilot hole helps in preventing the material from splitting and ensures proper alignment of the screw. To create one, you’d use a drill bit to make a smaller hole before driving in the screw.


Understanding what size drill bit to use for a #8 screw is crucial in achieving successful results in your drilling projects. Whether you are working with wood or metal, taking into account the specifics such as the screw size, the type of material, and the necessity for a pilot hole can guide you to make informed decisions. Remember to always refer to a reliable drill bit size chart to avoid mistakes and ensure the longevity of your constructions.

Remember, the goal is to have a project that not only looks good but is also sturdy and long-lasting. Equip yourself with the right knowledge and tools to excel in all your drilling endeavors.

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