5/16 Tap Drill Bit Size (Everything You Need to Know)

When it comes to drilling, having the right tools and knowledge is crucial for achieving accurate and precise results. One important aspect of drilling is the selection of the appropriate tap drill bit size.

In this comprehensive guide, I will discuss the details of the 5/16 tap drill bit size.

The tap drill bit size for a 5/16 tap is 17/64 inches. When choosing the correct tap drill bit size for a specific tapping operation, it is essential to match the tap size with the appropriate hole.

From its definition to its applications, I will cover everything you need to know to become an expert in this area. So, let’s get started!

What Size Drill Bit For A 5/16 Tap: Quick Overview

The optimal drill bit size to use with a 5/16″ – 18 tap is a 17/64″ drill bit, which is also referred to as an F drill bit.

Tap Size Drill Bit Size (inches) Drill Bit Size (millimeters)
5/16-18 tap drill size 17/64 6.75
5/16-24 tap drill size 9/32 7.14
5/16-32 tap drill size 17/64 6.75
5/16-36 tap drill size 9/32 7.14
5/16-40 tap drill size 9/32 7.14

The Importance Of The 5/16 Tap Drill Bit Size

Using the correct tap drill bit size is vital for achieving optimal results in drilling operations. Let’s explore some of its key benefits:

  • Accurate Thread Creation: The 5/16 tap drill bit enables the creation of precise and accurate threads with a 5/16-inch diameter. This is crucial when it comes to fitting screws, bolts, or other fasteners into corresponding holes. The right tap drill bit size ensures a proper fit, minimizing the risk of loose or stripped threads.
  • Enhanced Thread Strength: With the 5/16 tap drill bit, you can create threads that provide excellent strength and stability. This is particularly important in applications where the fastener components need to withstand heavy loads or vibrations. The right tap drill bit size ensures a secure connection, reducing the chances of thread failure.
  • Compatibility with Standardized Taps: The 5/16 tap drill bit is designed to match standardized tap sizes. This compatibility ensures ease of use and simplifies the selection process. By using the correct tap drill bit size, you can seamlessly pair it with a corresponding tap, allowing for efficient and precise threading.
  • Versatile Applications: The 5/16 tap drill bit finds application in various industries, including manufacturing, automotive, construction, and DIY projects. From creating threaded holes for fasteners to repairing damaged threads, this drill bit size offers versatility and flexibility for a wide range of tasks.

Common Applications of The Drill Size For 5/16 Tap

The 5/16 tap drill size has extensive applications across multiple industries and projects. Here are some common scenarios where this drill bit size is frequently utilized:

  • Metal Fabrication: In metal fabrication processes, the drill bit for 5 16 taps is often employed to create threaded holes in metal sheets, plates, or bars. These holes facilitate the insertion of screws, bolts, or studs, allowing for secure connections and assemblies.
  • Woodworking: When working with wood, the 5/16 tap drill bit is utilized to create threaded holes for joinery, furniture assembly, or installing hardware such as hinges or knobs. This ensures a sturdy and reliable connection between wooden components.
  • Automotive Repair: In automotive repair and maintenance, the 5/16 tap drill bit is commonly used to repair or replace damaged or worn-out threads in engine blocks, cylinder heads, or other components. This helps restore the integrity and functionality of the threaded connections.
  • Plumbing: The 5/16 tap drill bit is valuable in plumbing applications where threaded connections are necessary. From installing fixtures to repairing pipes, this drill bit size ensures a proper fit and prevents leaks or failures in the plumbing system.
  • Electronics and Electrical Work: When dealing with electronics or electrical installations, the drill size for a 5/16 tap enables the creation of threaded holes for cable glands, conduits, or mounting brackets. This facilitates the organization and secure installation of wires, cables, or electrical devices.

Factors to Consider When Choosing A Tap Drill Bit Size

Selecting the appropriate tap drill bit size requires careful consideration of several factors. By taking these factors into account, you can ensure optimal results and avoid potential issues during drilling operations. Here are some key factors to consider:

  • Thread Size and Pitch: Determine the desired thread size and pitch based on the requirements of your project. The 5/16 tap drill bit is specifically suitable for creating threads with a 5/16-inch diameter, but it’s important to match the pitch as well.
  • Material Being Drilled: Consider the type of material you will be drilling into. Different materials require different tap drill bit sizes to achieve the desired results. For example, drilling into metal may require a different size compared to drilling into wood or plastic.
  • Tap Type: Different taps have specific requirements in terms of drill bit sizes. Ensure that the tap you plan to use is compatible with the 5/16 tap drill bit size, or adjust your selection accordingly.
  • Depth of Hole: Take into account the depth of the hole you need to create. Ensure that the chosen tap drill bit size can reach the required depth without causing any issues.
  • Drilling Speed and Feed Rate: Consider the appropriate drilling speed and feed rate for the material being drilled. These parameters can affect the choice of tap drill bit size and the overall drilling process.

How To Measure And Identify A 5/16 Tap Drill Bit

Measuring and identifying the 5/16 tap drill bit is crucial to ensure accuracy and compatibility. Here’s a step-by-step guide to help you measure and identify the correct size:

  • Gather the Required Tools: Prepare a set of calipers or a drill bit gauge, along with the 5/16 tap drill bit you intend to measure.
  • Clean the Drill Bit: Ensure that the drill bit is clean and free from any debris or coatings that may interfere with accurate measurements.
  • Measure the Diameter: Use the calipers or drill bit gauge to measure the diameter of the drill bit. Adjust the calipers until they fit snugly around the drill bit, and then read the measurement displayed.
  • Verify the Size: Compare the measured diameter with the standard dimensions for the 5/16 tap drill bit. If they match, you have successfully identified the correct size.

Tips For Using The 5/16 Tap Drill Bit

To maximize the effectiveness of the drill bit for 5 16 taps and ensure successful drilling operations, consider the following tips:

  • Use Lubrication: Applying a suitable lubricant to the drill bit and the material being drilled can reduce friction and heat generation. This promotes smoother drilling and prolongs the life of the drill bit.
  • Controlled Pressure: Apply controlled and steady pressure when drilling. Excessive force may cause the drill bit to bind or break, while insufficient pressure can result in inefficient drilling.
  • Monitor Speed: Adjust the drilling speed based on the material being drilled. Lower speeds are generally recommended for harder materials, while higher speeds may be suitable for softer materials.
  • Clearing Chips: Regularly clear the chips and debris generated during drilling. This prevents them from clogging the hole or causing damage to the drill bit.

Frequently Asked Questions

What Size Drill Bit Do I Need For A 5/16 Tap?

To achieve the best results, you will need a 17/64 drill bit for a 5/16 tap.

How Do I Choose The Right Drill Bit Size For Tapping?

To choose the right drill bit size for tapping, you should refer to a tap drill chart, which lists the corresponding sizes for each tap.

What Happens If The Drill Bit Size Is Too Small For Tapping?

Using a drill bit smaller than the recommended size can result in stripped or damaged threads.

Can I Use A Larger Drill Bit For Tapping?

Using a larger drill bit can cause the tapped hole to be oversized, potentially leading to loose threads.

Are There Any Specific Considerations When Tapping A Hole?

Make sure to align the tap perpendicular to the workpiece, use cutting fluid for lubrication, and tap at a steady speed.


Understanding the 5/16 tap drill bit size is essential for anyone working with threads and bolts. By accurately matching the tap drill bit size with the desired thread size, you can ensure a secure and tight connection.

Whether you’re a DIY enthusiast or a professional in the field, having the right tools and knowledge is crucial.

Keep in mind that the 5/16 tap drill bit is designed specifically for creating holes that will accommodate the 5/16 thread. Investing in a high-quality tap drill bit of the appropriate size will help you achieve precise and reliable results.

Robert Carlson

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