What Size Drill Bit For #8 or #10 Screw [with Pilot Holes Chart]

Screws are typically designed with pointed ends that can be self-drilled. However, depending on the material, such as wood, you may need to drill pilot holes to avoid material degradation.

Using the right and knowing when to use the drill bit makes it more likely you’ll accomplish the job correctly the first time. However, with diverse applications for these instruments, various drill bits are out there for specific purposes.

According to the United States Department of Agriculture, “the rounding of the cutting edges and drilling resistance were relatively constant within the experimental conditions, indicating that resistance drilling measurement in wood was still accurate.”

In this article, we’ll explore the question “what size drill bit for #8 #10 screws,” so let’s start drilling.

What are Pilot Holes, and Why Is It Important?

Pilot holes are holes bored into building materials. The larger drills are guided to the precise spot by the smaller ones, which simplifies the task.

Furthermore, it allows the use of a punch, such as a knockout blow, to make the ultimate hole size. In addition, it helps to prevent breaking the screw by locating, guiding, and providing clearance for self-threading screw-in materials.

To install a screw in concrete or plastic, you can use pilot holes normally used when driving a screw.

When a screw is pushed into a substance without creating a pilot hole, it will turn into a pile driver. It results in a counterforce, which may cause many materials to break apart.

When you get the pilot hole correct, the screw won’t bind, remaining tight. The pilot hole in typical wood screws provides room for the screw’s core.  

Some people may also refer to a pilot hole as a hole drilled for tapping machine screws or bolt threads in metal.

Standard wood screws benefit from specially designed pilot drill bits, which cut a perfect hole profile with only one drill. If you need multiple drill bit sizes and depths, this one is the superior option.

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In addition, the size of the pilot hole for screws installed in concrete must be appropriate. Failure will occur with a broken seal, stripped bore, or holding power if you fail to consider this aspect.

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When Do You Need A Pilot Hole?

Pilot holes are important if you’re drilling through hardwood, laminate, or require a precisely positioned fastener. When aesthetics or the chance of cracking is a concern, they are also suggested.

A crude softwood frame needn’t have pilot holes, as the finished product won’t be seen. However, there are always exceptions to these generalizations.

One reason screws in pilot holes are generally neater than those hammered in by brute force is because of their cleanliness. In addition, the wood is more protected from cracking because it has been removed to make way for the screw.

Thus, there are certain instances where it is a must to drill a pilot hole. Also, there are a couple of scenarios when you can omit this step. The procedures in which a pilot hole may be required include these:

Aesthetic Considerations

A screw driven into wood with a hammer is harder to install than a screw driven into a pre-drilled hole. This factor, in turn, can result in a less beautiful finish.

You are slipping your drill bit off the screw without drilling a pilot hole, leaving an unattractive impression in the wood. It will stand out from the wood slightly if the screw doesn’t go as far in with a pilot hole as it would normally.  

Check The Screwing Location

Drill a pilot hole before screwing it into smaller wood or at the edge of the wood.

The added weight of the screw could stress the wood and cause it to split if you put it closer to the edge.

Pilot holes provide an additional area for the screw to travel through by removing the excessive wood first. It helps the wood to remain more durable.


Laminate is a flatter, smoother material than many others. You won’t be able to break through that material or create the first dent in it.

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The process of putting a screw in without first drilling a hole is cumbersome. But the screw wiggles about without even getting close to the wood/laminate.

First, you should drill a pilot hole. Second, you can rest assured that your screw will be right where you want it.

Type of Wood Involved

Compared to driving a screw into softwoods, it requires significantly greater force to achieve the same as hardwoods. It means that your drill is more likely to slip and scratch the wood. In the worst scenario, the board will stick with the tool at the wrong location.  

In addition to being denser, hardwoods also produce higher pressure inside the wood. It is because there is no pilot hole without one.

Drilling a pilot hole helps to alleviate this pressure since it creates space for the screw. Hence, drilling a pilot hole before working with hardwoods is recommended.

Screw Quality

You will have an easier time driving screws into the hole if we first drill pilot holes. It is important if you are using a low-grade screw.

Remember, striping is simpler and more likely to shatter when you apply significant pressure to low-quality screws. Plus, extracting a screw that is partially stuck in wood with its top broken off is virtually impossible.  

Standard Drill Bit Sizes For Pilot Holes

There are various drill bit sizes to select from to ensure that every project gets finished without fail. Each drill bit employs different naming conventions to improve accuracy, including letters, numbers, and fractions.

Drill bits are always part of 64ths, which is why measuring them is so important. The smallest is 64th of the size, while the largest is 63/64ths.

After that, you would convert them to the smallest fractional representation: 2/64 would be 1/32.

Additionally, the range of numbers will be between 1-80, with the smallest drill bit being the biggest.

It is necessary to make numerous distinct considerations when choosing what size drill bit for the #8 #10 screw. To be accurate, you have to consider screw type, materials, and thread design.

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In line with this, make sure that you have a variety of lengths on hand. Choose a screw that will pierce the concrete 1 in. Add one in. to the thickness of the material.

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How To Drill Pilot Holes?

If you want to screw or nail pieces of wood together, try using pilot holes first, which will save you time. These sound strategies will make the project easier and keep your wood safe:

Step 01 – Mark The Screwing Location

Mark the location of the hole with a pencil before you start drilling. You should be able to dent the wood a bit – softwood should be easy to dent.

Keep in mind that hardwood is more difficult. This dent will ensure that the drill bit is properly placed at the start of drilling.

Step 02 – Choose the Corresponding Drill Bit Size

You’re in search of a drill bit of the same diameter as the screw. To avoid the need for turning the screw in reverse, some advise using a drill bit that matches the diameter of the screw but has no threads.

That’s nice; however, sometimes you’re unaware of the screw diameters. For a flawless job, get a drill bit that is just a bit smaller than the screw.

Step 03 – Secure The Materials To Drill

Set the drill bit in the drill, then align the box with the mark you made in step one. Before the process, be sure to set the tool to turn in a clockwise direction.

Therefore, first, only use a small amount of pressure. You’ll need to have a good grip on the wood before your drill starts drilling.

To increase drilling speed, press the button down firmly while drilling straight. You should keep an eye on the drill bit depth as you go if you don’t want to damage your wood.

Step 04 – Start Drilling With A Correct Angle

Wear protective eyewear before drilling into the wood to avoid annoyance by sawdust that comes out of the pilot hole. Push the drill bit’s tip into the hole you made previously and hold the drill perpendicular to the wood.

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First, use a low-speed drill. If you can manage the tool, gradually increase your speed; otherwise, maintain a slow pace.

Step 05 – Screw-In

You should install screws and nails to the same depth as your pilot hole. For those with less experience, it is possible to mark the correct depth with a drill stop.

Slowly pull back the drill bit out of the hole, keeping the drill perpendicular to the wood as you do so.

Frequently Asked Questions (FAQs):

How Big A Pilot Hole Should I Drill?

In general, the size of the pilot hole should be equal to the diameter of the screw’s root. It allows for the screw to be inserted without splitting the wood’s grain. However, it still allows the threads to work together to draw two boards into a junction.

Many people don’t know how to drill pilot holes properly; thus, they create undersized holes. The wood screws are tightened extra-tight because they feel it strengthens the connection. That’s not necessarily true.

Do You Have To Drill Pilot Holes All The Way Through?

Drilling pilot holes all the way through the joint can weaken it. The threads become entangled in the initial piece, which locks it in place.

The screw can keep the two sections apart, making it more likely that a screw will get jammed or blocked.

When Should You Drill A Pilot Hole In Metal?

It is advised to create a pilot hole or indentation in the metal before beginning the job, as drill bits can be prone to going off track as soon as drilling commences. You may create a shallow dent in the metal with a nail and a hammer.

This shallow dip in the metal will allow you to maintain your drill straight, leading to a clean hole pierced through the metal.

What Drill Bit Size Works For #8 Screw?

A #29 drill bit will be ideal for your pilot hole if you have type A, AB, or B self-tapping screws. It can also work for type 25 thread-cutting screws.  

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For #8 screw fasteners in materials with a flexural modulus of 200,000 PSI or greater, the drill bit suggestion is a #30. If you’re using anything below a hardness of #31, a #31 drill bit is a preferable option.

You may use a drill bit of size #27 if using a #8 hammer drive or U-drive screw.

What Drill Bit Size Works For #10 Screw

You must get a #21 drill bit for a pilot hole if you have the type A self-tapping screws. This drill also works for type AB self-tapping screws, type B self-tapping screws, or type 25 thread-cutting screws.

For materials with a flexural modulus of over 200,000 PSI, the suggested drill bit for a #10 screw is a #27. When drilling with materials that are below the recommended value, #29 drill bits are preferable.

Key Takeaway

Indeed a micro-hole can produce a macro effect for your projects or task. In line with this, it is essential to know what size drill bit for the #8 and #10 screws you’ll use.

You can achieve accuracy with every project using a proper choice of drill bit sizes. Every naming convention has a different purpose and includes letters, numbers, and fractions.

If you can understand all of the requirements, you can be sure that your project will succeed. Remember, your screws are important, so take care of them with pilot holes.

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